NOIP2012 借教室

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
using namespace std;
const int maxn = 1050000;
long long n,m,r[maxn],d[maxn],s[maxn],t[maxn],sum[maxn];
void input(){
    cin>>n>>m;
    for(int i = 1;i <= n;i++) scanf("%lld",&r[i]);
    for(int i = 1;i <= m;i++) scanf("%lld%lld%lld",&d[i],&s[i],&t[i]);
}
bool check(int tg){
    if(!tg) return true;
    memset(sum,0,sizeof(sum));
    for(int i = 1;i <= tg;i++){
        sum[s[i]] += d[i];
        sum[t[i] + 1] -= d[i];
    }
    long long add = 0;
    for(int i = 1;i <= n;i++){
        add += sum[i];
        if(add > r[i]) return false;
    }
    return true;    
}
void div(){
    int lans = 0,rans = m,mans;
    while(lans <= rans){
        mans = (lans + rans) >> 1;
        if(check(mans)){
            lans = mans + 1;
        }else{
            rans = mans - 1;
        }
    }
    if(!check(mans)) mans--;
    if(mans == m) cout<<0;
    else{
        cout<<-1<<endl<<mans+1;
    }
    return;
}
int main(){
    input();
    div();
    return 0;
}