差分解法（适合GESP4级）

代码如下：

#include <iostream>
using namespace std;

const int N = 5000010;

int main() {
    int n, p;
    cin >> n >> p;
    
    int a[N];
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
    }
    
    int d[N] = {0};
    
    while (p--) {
        int x, y, z;
        cin >> x >> y >> z;
        d[x] += z;
        if (y + 1 <= n) d[y + 1] -= z;
    }
    
    int min = 300;
    for (int i = 1; i <= n; ++i) {
        d[i] += d[i - 1];
        int now = a[i] + d[i];
        if (now < min) min = now;
    }
    
    cout << min << endl;
    return 0;
}