C++ :

#include<bits/stdc++.h>
using namespace std;

const int N = 500010;
int a[N],b[N];//a原数组，b差分数组 
int n,p;

void insert(int l,int r,int v){
	b[l] = b[l] + v;
	b[r+1] = b[r+1] - v; 
}

int main() {
	cin>>n>>p;
	for(int i = 1;i <= n;i++) scanf("%d",&a[i]);
	
	//求a数组的差分数组 
	for(int i = 1;i <= n;i++) insert(i,i,a[i]);
	
	//p次加分
	int l,r,v;
	for(int i = 1;i <= p;i++){
		scanf("%d%d%d",&l,&r,&v);
		insert(l,r,v);
	} 
	
	//求每个人的分数
	int mi = INT_MAX;
	for(int i = 1;i <= n;i++){
		b[i] = b[i] + b[i-1];
		mi = min(mi,b[i]);
	} 
	cout<<mi;
	return 0;
}