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feat: add solutions to lc problem: No.0336
No.0336.Palindrome Pairs
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‎README.md

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@@ -62,6 +62,7 @@
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- [带限制的子序列和](/solution/1400-1499/1425.Constrained%20Subsequence%20Sum/README.md) - `动态规划`、`单调队列优化`
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- [单词规律 II](/solution/0200-0299/0291.Word%20Pattern%20II/README.md) - `哈希表`、`回溯`
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- [最短回文串](/solution/0200-0299/0214.Shortest%20Palindrome/README.md) - `字符串哈希`
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- [回文对](/solution/0300-0399/0336.Palindrome%20Pairs/README.md) - `字符串哈希`
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### 3. 搜索
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‎README_EN.md

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@@ -60,6 +60,7 @@ Complete solutions to [LeetCode](https://leetcode.com/problemset/all/), [LCOF](h
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- [Constrained Subsequence Sum](/solution/1400-1499/1425.Constrained%20Subsequence%20Sum/README_EN.md) - `Dynamic Programming`, `Monotonic Queue`
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- [Word Pattern II](/solution/0200-0299/0291.Word%20Pattern%20II/README_EN.md) - `Hash Table`、`Backtracking`
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- [Shortest Palindrome](/solution/0200-0299/0214.Shortest%20Palindrome/README_EN.md) - `Rabin-Karp`
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- [Palindrome Pairs](/solution/0300-0399/0336.Palindrome%20Pairs/README_EN.md)) - `Rabin-Karp`
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### 3. Search
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‎solution/0300-0399/0336.Palindrome Pairs/README.md

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<!-- 这里可写通用的实现逻辑 -->
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**方法一：字符串哈希**
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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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```java
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class Solution {
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private static final int BASE = 131;
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private static final long[] MUL = new long[310];
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private static final int MOD = (int) 1e9 + 7;
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static {
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MUL[0] = 1;
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for (int i = 1; i < MUL.length; ++i) {
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MUL[i] = (MUL[i - 1] * BASE) % MOD;
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}
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}
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public List<List<Integer>> palindromePairs(String[] words) {
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int n = words.length;
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long[] prefix = new long[n];
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long[] suffix = new long[n];
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for (int i = 0; i < n; ++i) {
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String word = words[i];
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int m = word.length();
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for (int j = 0; j < m; ++j) {
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int t = word.charAt(j) - 'a' + 1;
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int s = word.charAt(m - j - 1) - 'a' + 1;
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prefix[i] = (prefix[i] * BASE) % MOD + t;
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suffix[i] = (suffix[i] * BASE) % MOD + s;
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}
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}
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List<List<Integer>> ans = new ArrayList<>();
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for (int i = 0; i < n; ++i) {
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for (int j = i + 1; j < n; ++j) {
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if (check(i, j, words[j].length(), words[i].length(), prefix, suffix)) {
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ans.add(Arrays.asList(i, j));
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}
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if (check(j, i, words[i].length(), words[j].length(), prefix, suffix)) {
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ans.add(Arrays.asList(j, i));
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}
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}
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}
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return ans;
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}
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private boolean check(int i, int j, int n, int m, long[] prefix, long[] suffix) {
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long t = ((prefix[i] * MUL[n]) % MOD + prefix[j]) % MOD;
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long s = ((suffix[j] * MUL[m]) % MOD + suffix[i]) % MOD;
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return t == s;
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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 palindromePairs(words []string) [][]int {
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base := 131
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mod := int(1e9) + 7
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mul := make([]int, 310)
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mul[0] = 1
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for i := 1; i < len(mul); i++ {
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mul[i] = (mul[i-1] * base) % mod
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}
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n := len(words)
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prefix := make([]int, n)
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suffix := make([]int, n)
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for i, word := range words {
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m := len(word)
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for j, c := range word {
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t := int(c-'a') + 1
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s := int(word[m-j-1]-'a') + 1
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prefix[i] = (prefix[i]*base)%mod + t
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suffix[i] = (suffix[i]*base)%mod + s
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}
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}
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check := func(i, j, n, m int) bool {
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t := ((prefix[i]*mul[n])%mod + prefix[j]) % mod
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s := ((suffix[j]*mul[m])%mod + suffix[i]) % mod
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return t == s
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}
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var ans [][]int
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for i := 0; i < n; i++ {
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for j := i + 1; j < n; j++ {
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if check(i, j, len(words[j]), len(words[i])) {
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ans = append(ans, []int{i, j})
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}
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if check(j, i, len(words[i]), len(words[j])) {
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ans = append(ans, []int{j, i})
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}
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}
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}
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return ans
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}
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```
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### **...**

‎solution/0300-0399/0336.Palindrome Pairs/README_EN.md

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### **Java**
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```java
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class Solution {
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private static final int BASE = 131;
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private static final long[] MUL = new long[310];
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private static final int MOD = (int) 1e9 + 7;
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static {
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MUL[0] = 1;
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for (int i = 1; i < MUL.length; ++i) {
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MUL[i] = (MUL[i - 1] * BASE) % MOD;
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}
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}
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public List<List<Integer>> palindromePairs(String[] words) {
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int n = words.length;
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long[] prefix = new long[n];
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long[] suffix = new long[n];
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for (int i = 0; i < n; ++i) {
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String word = words[i];
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int m = word.length();
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for (int j = 0; j < m; ++j) {
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int t = word.charAt(j) - 'a' + 1;
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int s = word.charAt(m - j - 1) - 'a' + 1;
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prefix[i] = (prefix[i] * BASE) % MOD + t;
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suffix[i] = (suffix[i] * BASE) % MOD + s;
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}
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}
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List<List<Integer>> ans = new ArrayList<>();
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for (int i = 0; i < n; ++i) {
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for (int j = i + 1; j < n; ++j) {
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if (check(i, j, words[j].length(), words[i].length(), prefix, suffix)) {
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ans.add(Arrays.asList(i, j));
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}
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if (check(j, i, words[i].length(), words[j].length(), prefix, suffix)) {
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ans.add(Arrays.asList(j, i));
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}
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}
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}
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return ans;
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}
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private boolean check(int i, int j, int n, int m, long[] prefix, long[] suffix) {
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long t = ((prefix[i] * MUL[n]) % MOD + prefix[j]) % MOD;
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long s = ((suffix[j] * MUL[m]) % MOD + suffix[i]) % MOD;
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return t == s;
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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 palindromePairs(words []string) [][]int {
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base := 131
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mod := int(1e9) + 7
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mul := make([]int, 310)
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mul[0] = 1
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for i := 1; i < len(mul); i++ {
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mul[i] = (mul[i-1] * base) % mod
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}
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n := len(words)
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prefix := make([]int, n)
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suffix := make([]int, n)
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for i, word := range words {
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m := len(word)
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for j, c := range word {
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t := int(c-'a') + 1
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s := int(word[m-j-1]-'a') + 1
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prefix[i] = (prefix[i]*base)%mod + t
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suffix[i] = (suffix[i]*base)%mod + s
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}
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}
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check := func(i, j, n, m int) bool {
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t := ((prefix[i]*mul[n])%mod + prefix[j]) % mod
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s := ((suffix[j]*mul[m])%mod + suffix[i]) % mod
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return t == s
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}
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var ans [][]int
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for i := 0; i < n; i++ {
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for j := i + 1; j < n; j++ {
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if check(i, j, len(words[j]), len(words[i])) {
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ans = append(ans, []int{i, j})
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}
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if check(j, i, len(words[i]), len(words[j])) {
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ans = append(ans, []int{j, i})
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}
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}
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}
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return ans
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}
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```
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### **...**

‎solution/0300-0399/0336.Palindrome Pairs/Solution.go

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func palindromePairs(words []string) [][]int {
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base := 131
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mod := int(1e9) + 7
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mul := make([]int, 310)
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mul[0] = 1
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for i := 1; i < len(mul); i++ {
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mul[i] = (mul[i-1] * base) % mod
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}
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n := len(words)
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prefix := make([]int, n)
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suffix := make([]int, n)
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for i, word := range words {
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m := len(word)
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for j, c := range word {
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t := int(c-'a') + 1
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s := int(word[m-j-1]-'a') + 1
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prefix[i] = (prefix[i]*base)%mod + t
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suffix[i] = (suffix[i]*base)%mod + s
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}
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}
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check := func(i, j, n, m int) bool {
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t := ((prefix[i]*mul[n])%mod + prefix[j]) % mod
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s := ((suffix[j]*mul[m])%mod + suffix[i]) % mod
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return t == s
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}
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var ans [][]int
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for i := 0; i < n; i++ {
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for j := i + 1; j < n; j++ {
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if check(i, j, len(words[j]), len(words[i])) {
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ans = append(ans, []int{i, j})
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}
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if check(j, i, len(words[i]), len(words[j])) {
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ans = append(ans, []int{j, i})
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}
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}
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}
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return ans
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}

‎solution/0300-0399/0336.Palindrome Pairs/Solution.java

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class Solution {
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private static final int BASE = 131;
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private static final long[] MUL = new long[310];
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private static final int MOD = (int) 1e9 + 7;
5+
static {
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MUL[0] = 1;
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for (int i = 1; i < MUL.length; ++i) {
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MUL[i] = (MUL[i - 1] * BASE) % MOD;
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}
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}
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public List<List<Integer>> palindromePairs(String[] words) {
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int n = words.length;
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long[] prefix = new long[n];
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long[] suffix = new long[n];
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for (int i = 0; i < n; ++i) {
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String word = words[i];
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int m = word.length();
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for (int j = 0; j < m; ++j) {
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int t = word.charAt(j) - 'a' + 1;
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int s = word.charAt(m - j - 1) - 'a' + 1;
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prefix[i] = (prefix[i] * BASE) % MOD + t;
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suffix[i] = (suffix[i] * BASE) % MOD + s;
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}
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}
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List<List<Integer>> ans = new ArrayList<>();
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for (int i = 0; i < n; ++i) {
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for (int j = i + 1; j < n; ++j) {
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if (check(i, j, words[j].length(), words[i].length(), prefix, suffix)) {
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ans.add(Arrays.asList(i, j));
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}
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if (check(j, i, words[i].length(), words[j].length(), prefix, suffix)) {
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ans.add(Arrays.asList(j, i));
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}
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}
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}
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return ans;
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}
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private boolean check(int i, int j, int n, int m, long[] prefix, long[] suffix) {
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long t = ((prefix[i] * MUL[n]) % MOD + prefix[j]) % MOD;
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long s = ((suffix[j] * MUL[m]) % MOD + suffix[i]) % MOD;
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return t == s;
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}
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}

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