一维差分：复杂度 $O(n+k)$

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N = 1e6 + 10, INF = 0x3f3f3f3f;
int n, k, a[N], d[N], l, r, c;

int main() {
    cin >> n >> k;
    for (int i = 1; i <= n; i++)
        cin >> a[i], d[i] = a[i] - a[i - 1];
    while (k--) {
        cin >> l >> r >> c;
        d[l] += c;
        d[r + 1] -= c;
    }
    for (int i = 1; i <= n; i++) {
        d[i] += d[i - 1];
        cout << d[i] << " ";
    }
    return 0;
}