f[i],以i为结尾的最大上升子序列和

#include <iostream>

using namespace std;

const int N = 1010;
int a[N], f[N];

int main() {
    int n;
    cin >> n;
    for(int i = 1; i <= n; i++) cin >> a[i];
    for(int i = 1; i <= n; i++) {
        f[i] = a[i];
        for(int j = 1; j < i; j++)
            if(a[j] < a[i]) f[i] = max(f[i], f[j] + a[i]);
    }
    int res = 0;
    for(int i = 1; i <= n; i++) res = max(res, f[i]);
    cout << res;
    return 0;
}