题解 | 最大上升子序列和

#include <iostream>
#include <algorithm>
#include <string>
#include <cstdio>

using namespace std;

//最大上升子序列和
//区别于最长上升子序列，此时集合的属性为最大子序列和，即状态数组f[i]记录以a[i]结尾的
//最大上升子序列和

const int N = 1001;
int n;
int a[N], f[N];

int res() {
    //处理边界
    if (n == 0)return 0;
    for (int i = 0; i < n; i++) f[i] = a[i];//初始化状态数组
    int ma = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < i; j++) {
            if (a[j] < a[i])
                f[i] = max(f[i], f[j] + a[i]);
        }
    }
    for (int i = 0; i < n; i++) ma = max(ma, f[i]);
    return ma;
}

int main() {
    cin >> n;
    for (int i = 0; i < n; i++) cin >> a[i];
    cout << res() << endl;
    return 0;
}