题解 | #跳跃游戏(二)#

#include <iostream>
#include<cstring>

using namespace std;

const int N = 100010;
int a[N], f[N];

int jump(int n){
    if(n == 0) return -1;
    if(n == 1) return a[0];
    f[0] = a[0];
    for(int i = 0; i < n; i ++){
        if(f[i] != -1){
            int maxReach = min(n - 1, i + a[i]);
            for(int j = i + 1; j <= maxReach; j ++){
                f[j] = max(f[j], f[i] + a[j]);
            }
        }
    }
    return f[n - 1];
}

int main() {
    int n;
    cin >> n;
    memset(f, -1, sizeof f);
    for (int i = 0; i < n; i ++) {
        cin >> a[i];
    }
    cout << jump(n) << endl;
    return 0;
}