#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <algorithm>
using namespace std;
#define N 1000010
int n,m,r[N],d[N],s[N],t[N];
int sum[N];

int read ()
{
	int s=0,k=1;char c=getchar ();
	while (!isdigit (c)) {if (c=='-') k=-1;c=getchar ();}
	while (isdigit (c)) {s=s*10+c-'0';c=getchar ();}
	return k*s;
}

void Init ()
{
	n=read (),m=read ();
	for (int i=1;i<=n;i++)
		r[i]=read ();
	for (int i=1;i<=m;i++)
		d[i]=read (),s[i]=read (),t[i]=read ();
}

bool check (int x)
{
	memset (sum,0,sizeof (sum));
	for (int i=1;i<=x;i++)
	{
		sum[s[i]]+=d[i];
		sum[t[i]+1]-=d[i];
	}
	for (int i=1;i<=n;i++)
	{
		sum[i]+=sum[i-1];
		if (sum[i]>r[i])
			return false;
	}
	return true;
}

void Work ()
{
	int L=0,R=m,mid;
	while (L<R)
	{
		int mid=(L+R)>>1;
		if (check (mid)) L=mid;
		else R=mid-1;
	}
	if (mid==n) puts ("0");
	else
	{
		puts ("-1");
		printf ("%d\n",L+1);
	}
}

int main ()
{
	Init ();
	Work ();
	return 0;
}

为什么超时