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feat: add solutions to lc problem: No.0564
No.0564.Find the Closest Palindrome
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‎solution/0500-0599/0564.Find the Closest Palindrome/README.md

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<!-- 这里写题目描述 -->
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<p>给定一个整数 n ，你需要找到与它最近的回文数（不包括自身）。</p>
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<p>给定一个表示整数的字符串&nbsp;<code>n</code> ，返回与它最近的回文整数（不包括自身）。如果不止一个，返回较小的那个。</p>
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<p>&ldquo;最近的&rdquo;定义为两个整数<strong>差的绝对值</strong>最小。</p>
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<p>“最近的”定义为两个整数<strong>差的绝对值</strong>最小。</p>
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<p>&nbsp;</p>
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<p><strong>示例 1:</strong></p>
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<pre>
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<strong>输入:</strong> &quot;123&quot;
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<strong>输出:</strong> &quot;121&quot;
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<strong>输入:</strong> n = "123"
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<strong>输出:</strong> "121"
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</pre>
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<p><strong>示例 2:</strong></p>
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<pre>
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<strong>输入:</strong> n = "1"
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<strong>输出:</strong> "0"
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<strong>解释:</strong> 0 和 2是最近的回文，但我们返回最小的，也就是 0。
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</pre>
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<p><strong>注意:</strong></p>
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<p>&nbsp;</p>
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<p><strong>提示:</strong></p>
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<ol>
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<li><strong>n </strong>是由字符串表示的正整数，其长度不超过18。</li>
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<li>如果有多个结果，返回最小的那个。</li>
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</ol>
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<ul>
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<li><code>1 &lt;= n.length &lt;= 18</code></li>
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<li><code>n</code>&nbsp;只由数字组成</li>
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<li><code>n</code>&nbsp;不含前导 0</li>
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<li><code>n</code>&nbsp;代表在&nbsp;<code>[1, 10<sup>18</sup>&nbsp;- 1]</code> 范围内的整数</li>
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</ul>
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## 解法
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<!-- 这里可写通用的实现逻辑 -->
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- 用原数的前半部分替换后半部分得到的回文整数。
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- 用原数的前半部分加一后的结果替换后半部分得到的回文整数。
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- 用原数的前半部分减一后的结果替换后半部分得到的回文整数。
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- 为防止位数变化导致构造的回文整数错误，因此直接构造 999999…999 和 100…001 作为备选答案。
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求以上数字中，最接近原数且不等于原数的最小数字。
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<!-- tabs:start -->
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
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class Solution:
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def nearestPalindromic(self, n: str) -> str:
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x = int(n)
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l = len(n)
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res = {10 ** (l - 1) - 1, 10 ** l + 1}
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left = int(n[:(l + 1) >> 1])
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for i in range(left - 1, left + 2):
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j = i if l % 2 == 0 else i // 10
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while j:
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i = i * 10 + j % 10
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j //= 10
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res.add(i)
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res.discard(x)
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ans = -1
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for t in res:
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if ans == -1 or abs(t - x) < abs(ans - x) or (abs(t - x) == abs(ans - x) and t < ans):
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ans = t
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return str(ans)
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
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class Solution {
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public String nearestPalindromic(String n) {
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long x = Long.parseLong(n);
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long ans = -1;
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for (long t : get(n)) {
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if (ans == -1 || Math.abs(t - x) < Math.abs(ans - x) || (Math.abs(t - x) == Math.abs(ans - x) && t < ans)) {
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ans = t;
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}
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}
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return Long.toString(ans);
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}
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private Set<Long> get(String n) {
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int l = n.length();
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Set<Long> res = new HashSet<>();
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res.add((long) Math.pow(10, l - 1) - 1);
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res.add((long) Math.pow(10, l) + 1);
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long left = Long.parseLong(n.substring(0, (l + 1) / 2));
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for (long i = left - 1; i <= left + 1; ++i) {
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StringBuilder sb = new StringBuilder();
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sb.append(i);
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sb.append(new StringBuilder(i + "").reverse().substring(l & 1));
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res.add(Long.parseLong(sb.toString()));
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}
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res.remove(Long.parseLong(n));
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return res;
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}
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}
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```
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### **C++**
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```cpp
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class Solution {
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public:
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string nearestPalindromic(string n) {
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long x = stol(n);
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long ans = -1;
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for (long t : get(n))
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if (ans == -1 || abs(t - x) < abs(ans - x) || (abs(t - x) == abs(ans - x) && t < ans))
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ans = t;
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return to_string(ans);
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}
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unordered_set<long> get(string& n) {
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int l = n.size();
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unordered_set<long> res;
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res.insert((long)pow(10, l - 1) - 1);
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res.insert((long)pow(10, l) + 1);
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long left = stol(n.substr(0, (l + 1) / 2));
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for (long i = left - 1; i <= left + 1; ++i)
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{
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string prefix = to_string(i);
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string t = prefix + string(prefix.rbegin() + (l & 1), prefix.rend());
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res.insert(stol(t));
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}
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res.erase(stol(n));
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return res;
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}
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};
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```
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### **Go**
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```go
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func nearestPalindromic(n string) string {
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l := len(n)
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res := []int{int(math.Pow10(l-1)) - 1, int(math.Pow10(l)) + 1}
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left, _ := strconv.Atoi(n[:(l+1)/2])
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for _, x := range []int{left - 1, left, left + 1} {
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y := x
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if l&1 == 1 {
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y /= 10
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}
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for ; y > 0; y /= 10 {
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x = x*10 + y%10
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}
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res = append(res, x)
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}
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ans := -1
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x, _ := strconv.Atoi(n)
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for _, t := range res {
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if t != x {
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if ans == -1 || abs(t-x) < abs(ans-x) || abs(t-x) == abs(ans-x) && t < ans {
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ans = t
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}
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}
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}
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return strconv.Itoa(ans)
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}
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func abs(x int) int {
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if x < 0 {
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return -x
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}
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return x
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}
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```
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### **...**

‎solution/0500-0599/0564.Find the Closest Palindrome/README_EN.md

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@@ -41,13 +41,127 @@
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### **Python3**
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```python
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class Solution:
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def nearestPalindromic(self, n: str) -> str:
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x = int(n)
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l = len(n)
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res = {10 ** (l - 1) - 1, 10 ** l + 1}
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left = int(n[:(l + 1) >> 1])
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for i in range(left - 1, left + 2):
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j = i if l % 2 == 0 else i // 10
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while j:
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i = i * 10 + j % 10
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j //= 10
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res.add(i)
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res.discard(x)
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ans = -1
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for t in res:
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if ans == -1 or abs(t - x) < abs(ans - x) or (abs(t - x) == abs(ans - x) and t < ans):
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ans = t
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return str(ans)
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```
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### **Java**
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```java
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class Solution {
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public String nearestPalindromic(String n) {
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long x = Long.parseLong(n);
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long ans = -1;
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for (long t : get(n)) {
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if (ans == -1 || Math.abs(t - x) < Math.abs(ans - x) || (Math.abs(t - x) == Math.abs(ans - x) && t < ans)) {
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ans = t;
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}
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}
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return Long.toString(ans);
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}
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private Set<Long> get(String n) {
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int l = n.length();
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Set<Long> res = new HashSet<>();
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res.add((long) Math.pow(10, l - 1) - 1);
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res.add((long) Math.pow(10, l) + 1);
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long left = Long.parseLong(n.substring(0, (l + 1) / 2));
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for (long i = left - 1; i <= left + 1; ++i) {
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StringBuilder sb = new StringBuilder();
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sb.append(i);
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sb.append(new StringBuilder(i + "").reverse().substring(l & 1));
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res.add(Long.parseLong(sb.toString()));
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}
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res.remove(Long.parseLong(n));
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return res;
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}
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}
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```
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### **C++**
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```cpp
101+
class Solution {
102+
public:
103+
string nearestPalindromic(string n) {
104+
long x = stol(n);
105+
long ans = -1;
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for (long t : get(n))
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if (ans == -1 || abs(t - x) < abs(ans - x) || (abs(t - x) == abs(ans - x) && t < ans))
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ans = t;
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return to_string(ans);
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}
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unordered_set<long> get(string& n) {
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int l = n.size();
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unordered_set<long> res;
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res.insert((long)pow(10, l - 1) - 1);
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res.insert((long)pow(10, l) + 1);
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long left = stol(n.substr(0, (l + 1) / 2));
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for (long i = left - 1; i <= left + 1; ++i)
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{
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string prefix = to_string(i);
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string t = prefix + string(prefix.rbegin() + (l & 1), prefix.rend());
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res.insert(stol(t));
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}
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res.erase(stol(n));
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return res;
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}
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};
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```
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### **Go**
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```go
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func nearestPalindromic(n string) string {
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l := len(n)
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res := []int{int(math.Pow10(l-1)) - 1, int(math.Pow10(l)) + 1}
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left, _ := strconv.Atoi(n[:(l+1)/2])
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for _, x := range []int{left - 1, left, left + 1} {
138+
y := x
139+
if l&1 == 1 {
140+
y /= 10
141+
}
142+
for ; y > 0; y /= 10 {
143+
x = x*10 + y%10
144+
}
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res = append(res, x)
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}
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ans := -1
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x, _ := strconv.Atoi(n)
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for _, t := range res {
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if t != x {
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if ans == -1 || abs(t-x) < abs(ans-x) || abs(t-x) == abs(ans-x) && t < ans {
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ans = t
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}
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}
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}
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return strconv.Itoa(ans)
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}
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func abs(x int) int {
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if x < 0 {
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return -x
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}
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return x
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}
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```
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### **...**

‎solution/0500-0599/0564.Find the Closest Palindrome/Solution.cpp

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class Solution {
2+
public:
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string nearestPalindromic(string n) {
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long x = stol(n);
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long ans = -1;
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for (long t : get(n))
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if (ans == -1 || abs(t - x) < abs(ans - x) || (abs(t - x) == abs(ans - x) && t < ans))
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ans = t;
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return to_string(ans);
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}
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unordered_set<long> get(string& n) {
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int l = n.size();
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unordered_set<long> res;
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res.insert((long)pow(10, l - 1) - 1);
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res.insert((long)pow(10, l) + 1);
17+
long left = stol(n.substr(0, (l + 1) / 2));
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for (long i = left - 1; i <= left + 1; ++i)
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{
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string prefix = to_string(i);
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string t = prefix + string(prefix.rbegin() + (l & 1), prefix.rend());
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res.insert(stol(t));
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}
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res.erase(stol(n));
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return res;
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}
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};

‎solution/0500-0599/0564.Find the Closest Palindrome/Solution.go

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func nearestPalindromic(n string) string {
2+
l := len(n)
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res := []int{int(math.Pow10(l-1)) - 1, int(math.Pow10(l)) + 1}
4+
left, _ := strconv.Atoi(n[:(l+1)/2])
5+
for _, x := range []int{left - 1, left, left + 1} {
6+
y := x
7+
if l&1 == 1 {
8+
y /= 10
9+
}
10+
for ; y > 0; y /= 10 {
11+
x = x*10 + y%10
12+
}
13+
res = append(res, x)
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}
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ans := -1
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x, _ := strconv.Atoi(n)
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for _, t := range res {
18+
if t != x {
19+
if ans == -1 || abs(t-x) < abs(ans-x) || abs(t-x) == abs(ans-x) && t < ans {
20+
ans = t
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}
22+
}
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}
24+
return strconv.Itoa(ans)
25+
}
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27+
func abs(x int) int {
28+
if x < 0 {
29+
return -x
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}
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return x
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}

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