80分求助，#5RE了

#include <bits/stdc++.h>
using namespace std;
const int N = 1e6;
int a[N];
int main() {
    int n, p, x, y, z;
    cin >> n >> p;
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    for (int i = 1; i <= p; i++) {
        cin >> x >> y >> z;
        for (int i = x; i <= y; i++)
            a[i] += z;
    }
    sort(a + 1, a + n + 1, less<int>());
    cout << a[1];
    return 0;
}

求助大佬！