背包问题求具体方案

#include<bits/stdc++.h>
using namespace std;
const int N = 1010;
int n,m;
int v[N],w[N];
int f[N][N];
int main(){
    cin >> n >> m;
    for(int i = 1;i <= n;++i)cin >> v[i] >> w[i];
    for(int i = n ;i >= 1;--i){
        for(int j = 0;j <= m;++j){
            f[i][j] = f[i + 1][j];
            if(j >= v[i])
                f[i][j] = max(f[i][j],f[i + 1][j - v[i]] + w[i]);
        }
    }
    int j = m;
    for(int i = 1;i <= n;++i){
        //如果背包的容量还能放下 i 并且放与不放答案相同 那么就一定要选
        if(j >= v[i] && f[i][j] == f[i + 1][j - v[i]] + w[i]){
            cout << i << " " ;
            j -= v[i];
        }
    }
    return 0;
}