Manacher BestCoder Round #49 ($) 1002 Three Palindromes

题目传送门

 /*
     Manacher：该算法能求最长回文串，思路时依据回文半径p数组找到第一个和第三个会文串，然后暴力枚举判断是否存在中间的回文串
     另外，在原字符串没啥用时可以直接覆盖，省去一个数组空间，位运算 >>1 比 /2 速度快，用了程序跑快200ms左右，位运算大法好
 */
 /************************************************
 Author        :Running_Time
 Created Time  :2015-8-1 20:10:22
 File Name     :B.cpp
 *************************************************/

 #include <cstdio>
 #include <algorithm>
 #include <iostream>
 #include <sstream>
 #include <cstring>
 #include <cmath>
 #include <string>
 #include <vector>
 #include <queue>
 #include <deque>
 #include <stack>
 #include <list>
 #include <map>
 #include <set>
 #include <bitset>
 #include <cstdlib>
 #include <ctime>
 using namespace std;

 typedef long long ll;
 const int MAXN = 2e4 + ;
 const int INF = 0x3f3f3f3f;
 const int MOD = 1e9 + ;
 char s[MAXN*];
 int p[MAXN*], fi[MAXN*], ei[MAXN*];
 int len;

 void Manacher(void) {
     for (int i=len; i>=; --i)  {
         s[i*+] = s[i];    s[i*+] = '#';
     }
     s[] = '$'; len = len *  + ;
     int id = ; p[] = ;
     for (int i=; i<len; ++i)   {
         if (id + p[id] > i) p[i] = min (p[*id-i], id + p[id] - i);
         else    p[i] = ;
         while (s[i-p[i]] == s[i+p[i]])  p[i]++;
         if (id + p[id] < i + p[i])  id = i;
     }
 }

 bool judge(void) {
     int c1 = , c2 = ;
     for (int i=; i<len-; ++i) {
         if (p[i] == i)  fi[++c1] = i;
         if (i + p[i] == len)    ei[++c2] = i;
     }
     for (int i=; i<=c1; ++i)   {
         for (int j=; j<=c2; ++j)   {
             int l = fi[i] + p[fi[i]];
             int r = ei[j] - p[ei[j]];
             if (l > r)  continue;
             int mid = (l + r) >> ;
             if (p[mid] > (r - l + ) >> )   return true;
         }
     }
     return false;
 }

 int main(void)    {       //BestCoder Round #49 ($) 1002 Three Palindromes
     int T;  scanf ("%d", &T);
     while (T--) {
         scanf ("%s", s);
         len = strlen (s);
         if (len < )    {
             puts ("NO");    continue;
         }
         Manacher ();
         judge () ? puts ("Yes") : puts ("No");
     }

     return ;
 }