hdu 4632 回文子序列计数

水题

#include<iostream>
#include<stdio.h>
#include<cstring>
#include<algorithm>
#include<vector>
#define mod 10007
using namespace std;
char str[1002]; int dp[1002][1002],cas;
void work( )
{
    int len = strlen( str );
    memset( dp,0,sizeof(dp) );
    for( int i = 0; i < len; i++ )dp[i][i] = 1;
    for( int i = 1; i < len; i++ )
    for( int j = 0; j + i < len; j++ )
    {
        int t = i+j;
          dp[j][t] =  dp[j][t-1] + dp[j+1][t]; if( j+1 <= t-1 ) dp[j][t] -= dp[j+1][t-1];
        if( str[j] == str[t] )
        {
          if(  j+1 <= t-1 ) dp[j][t] +=  dp[j+1][t-1] + 1;
          else  dp[j][t]++;
        }
        dp[j][t] %=  mod; dp[j][t] += mod;
    }
    dp[0][len-1] %= mod;
    printf("Case %d: %d
",cas++,dp[0][len-1]);
}
int main( )
{
   int T; cas = 1;scanf("%d",&T);
   while( T-- ){
       scanf("%s",&str);work( );
   }
   return 0;
}