nyoj 308 Substring

Substring

时间限制：1000 ms  |  内存限制：65535 KB

难度：1

描述

You are given a string input. You are to find the longest substring of input such that the reversal of the substring is also a substring of input. In case of a tie, return the string that occurs earliest in input. 

Note well: The substring and its reversal may overlap partially or completely. The entire original string is itself a valid substring . The best we can do is find a one character substring, so we implement the tie-breaker rule of taking the earliest one first.

输入

The first line of input gives a single integer, 1 ≤ N ≤ 10, the number of test cases. Then follow, for each test case, a line containing between 1 and 50 characters, inclusive. Each character of input will be an uppercase letter ('A'-'Z').

输出

Output for each test case the longest substring of input such that the reversal of the substring is also a substring of input

样例输入

3                   ABCABAXYZXCVCX

样例输出

ABAXXCVCX

#include<stdio.h> #include<string.h> int main() {     int n,i,j,len,k,max;     char a[55],b[55],c[55][55];     scanf("%d",&n);     while(n--)     {         max=0;         memset(c,0,sizeof(c));         getchar();         scanf("%s",a);         len=strlen(a);         for(i=0;i<len;i++)             b[i]=a[len-i-1];         for(i=1;i<=len;i++)             for(j=1;j<=len;j++)                 if(a[i-1]==b[j-1])                 {                     c[i][j]=c[i-1][j-1]+1;                     if(c[i][j]>max)                     {                         max=c[i][j];                         k=i;                     }                 }         for(i=k-max;i<k;i++)             printf("%c",a[i]);         printf("\n");     }     return 0; }