CF1285B Just Eat It! （最大连续子段和）

Just Eat It!

思路：最大连续子段和：判断前缀和是否大于0，如果大于0对后面有贡献，否则置0.

#include <cstdio>
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <functional>
#include <set>
#include <vector>
#include <queue>
#include <cstring>
#include <stack>
#include <climits>
 
using namespace std;
 
#define ll long long
#define pb push_back
#define fi first
#define se second

void solve(){

    int T;
    cin >> T;
    while(T--){
        int n;
        cin >> n;
        vector<int > a(n);
        ll sum = 0;
        for(auto& x : a){
            cin >> x;
            sum += x;
        }
        vector<ll > dp(n + 1);
        ll Max = -1e9 * 1e5 - 1e9;
        for(int i = 1; i < n; ++i){
            if(dp[i - 1] + a[i - 1] > 0) dp[i] = dp[i - 1] + a[i - 1];
            else dp[i] = 0;
            Max = max(Max, dp[i]);
        }
        fill(dp.begin(), dp.end(), 0);
        for(int i = 2; i <= n; ++i){
            if(dp[i - 1] + a[i - 1] > 0) dp[i] = dp[i - 1] + a[i - 1];
            else dp[i] = 0;
            Max = max(Max, dp[i]);
        }
        if(sum > Max) cout << "yes" << endl;
        else cout << "no" << endl;
    }
}
 
int main(){
    
    // freopen("C:\\Users\\admin\\Desktop\\input.txt", "r", stdin);
    // freopen("C:\\Users\\admin\\Desktop\\output.txt", "w", stdout);
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    solve();
    
    return 0;
}