95分，求助!!!

#include<bits/stdc++.h>
#define M 1000005
using namespace std;
int n,m,a[M],d[M],s[M],t[M],pos[M];
bool pd(int x){
	memset(pos,0,sizeof(pos));
	for(int i=1;i<=x;++i){
		pos[s[i]]-=d[i];pos[t[i]+1]+=d[i];
	}
	for(int i=1;i<=n;++i){
		pos[i]+=pos[i-1];
		if(pos[i]+a[i]<0)return 0;
	}
	return 1;
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(NULL);cout.tie(NULL);
	cin>>n>>m;
	for(int i=1;i<=n;++i)cin>>a[i];
	for(int i=1;i<=m;++i)cin>>d[i]>>s[i]>>t[i];
	int l=1,r=n;
	while(l<r){
		int mid=l+r>>1;
		if(pd(mid))l=mid+1;
		else r=mid;
	}
	if(l==m+1)cout<<0;
	else {
		cout<<"-1\n"<<l;
	}
	return 0;
}

谢谢大佬！！