look like这一题，不过要改一下

#include<bits/stdc++.h>
using namespace std;
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    if (!(cin >> n)) {
        return 0;
    }
    vector<int> a(n + 1);
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
    }
    vector<long long> dp(n + 1, 0);
    dp[0] = -1e18;
    if (n >= 1) {
        dp[1] =a[1];
    }
    for (int i = 2; i <= n; ++i) {
        dp[i] = max(dp[i - 1], dp[i - 2]) + a[i];
    }
    cout << dp[n] << endl;
	return 0;
}