9251 LCS

#include <stdio.h>
#include <cstring>
#include <algorithm>
 
using namespace std;
 
int dp[1001][1001] = { 0 };
char a[1001], b[1001], result[1001] = { 0 };
 
int main() {
    scanf("%s %s", &a, &b);
    getchar();
 
    int n = strlen(a);
    int m = strlen(b);
 
    for (int i = 0; i <= n; i++) {
        dp[0][i] = 0;
    }
    for (int i = 0; i <= m; i++) {
        dp[i][0] = 0;
    }
 
    for (int j = 0; j < m; j++) {
        for (int i = 0; i < n; i++) {
            if (a[i] == b[j]) {
                dp[j + 1][i + 1] = dp[j][i] + 1;
            }
            else {
                dp[j + 1][i + 1] = max(dp[j][i + 1], dp[j + 1][i]);
            }
        }
    }
    
    int idx = 0,st=n-1;
    for (int j = m; j >=0; j--) {        
        int snum = dp[j][st];
        for (int i =st-1; i >=0; i--) {            
            if (dp[j][i] != snum) {
                result[idx++] = a[i];
                st = i;
                break;
            }            
        }        
    }
 
    for (int i = idx-1; i >=0; i--) {
        printf("%c", result[i]);
    }
    printf("%d", dp[m][n]);
}