hdu 1159 Common Subsequence（最长公共子序列，DP）

char s1[505], s2[505];
int dp[505][505];

int main(){

    while(scanf("%s%s",s1,s2)!=EOF){
        int l1=strlen(s1);
        int l2=strlen(s2);
        mem(dp,0);
        dp[0][0]=((s1[0]==s2[0])?1:0);
        rep(i,1,l1-1) if(s1[i]==s2[0]) dp[i][0]=1; else dp[i][0]=dp[i-1][0];
        rep(i,1,l2-1) if(s1[0]==s2[i]) dp[0][i]=1; else dp[0][i]=dp[0][i-1];
        rep(i,1,l1-1){
            rep(j,1,l2-1){
                if(s1[i]==s2[j]){
                    dp[i][j]=max( dp[i-1][j-1]+1,dp[i-1][j] );
                    dp[i][j]=max( dp[i][j],dp[i][j-1] );
                }else{
                    dp[i][j]=max( dp[i-1][j],dp[i][j-1] );
                }
            }
        }

        printf("%d\n",dp[l1-1][l2-1]);
    }

    return 0;
}