Pat 1040

题意是找最长对称子序列，我的算法先将子序列翻转，然后找最长公共连续子序列，同样是用动态规划，和LCS不同的是状态函数

#include<iostream>
#include<string.h>

using std::cin;
using std::cout;
using std::endl;

char str[1010],rstr[1010];
int m[1010][1010];
int max(int a, int b){
    return a > b ? a : b;
}
int LongestSym(char str[],char rstr[]){
    int length = strlen(str);
    int maxlen = 0, i, j, flag = 0,len = 0;
    for (i = 0; i < length; i++)
    {
        m[0][i] = 0;
        m[i][0] = 0;
    }
    for (i = 1; i <= length; i++)
        for (j = 1; j <= length; j++)
        {
            if (str[i - 1] == rstr[j - 1])
                m[i][j] = m[i - 1][j - 1] + 1;
            else m[i][j] = 0;
            if (m[i][j]>maxlen)
                maxlen = m[i][j];
        }
        return maxlen;
}
void reverse(char str[]){
    int len = strlen(str);
    int i, j;
    for (i = 0, j = len - 1; j >= 0; j--, i++)
        rstr[i] = str[j];
    rstr[i] = '\0';
}
int main(){
    freopen("1.in", "r", stdin);
    cin.get(str,1009);
    reverse(str);
    int longest = LongestSym(str,rstr);
    cout << longest << endl;
    return 0;
}