hipo 4 最长回文

#include<stdio.h>#include<iostream>#include<string.h>#include<algorithm>using namespace std;#define N 1000005char str[2 * N + 2] = { 0 };char st[N] = { 0 };int p[2 * N + 2] = { 0 };int func(char* s){int nn = strlen(s);int n = 2 * nn + 2;str[0] = '$';//str首位置赋值$  for (int i = 0; i <= nn; i++){str[2 * i + 2] = st[i];str[2 * i + 1] = '#';}int ans = -999;int mx = 0;//mx用来记录p[i]中到达的最右端的值  int id;//id用来记录p[i]延长至最右端的下标i  for (int i = 1; i<n; i++){if (mx > i)p[i] = min(p[2 * id - i], mx - i);//不太明白，待深思。。。。  elsep[i] = 1;while (str[i - p[i]] == str[i + p[i]])p[i]++;if (mx < i + p[i]){mx = i + p[i];id = i;}if (ans < p[i])ans = p[i];}return ans - 1;}int main(){int n;cin >> n;for (int i = 0; i < n; ++i){cin >> st;cout << func(st) << endl;}return 0;｝