tyvj 2075 [NOIP2012T5]借教室 区间更新+二分

#include<iostream>
#include<cstdio>
#include<cmath>
#include<string>
#include<queue>
#include<algorithm>
#include<stack>
#include<cstring>
#include<vector>
#include<list>
#include<set>
#include<map>
using namespace std;
#define ll __int64
#define mod 1000000007
int scan()
{
    int res = 0 , ch ;
    while( !( ( ch = getchar() ) >= ‘0‘ && ch <= ‘9‘ ) )
    {
        if( ch == EOF )  return 1 << 30 ;
    }
    res = ch - ‘0‘ ;
    while( ( ch = getchar() ) >= ‘0‘ && ch <= ‘9‘ )
        res = res * 10 + ( ch - ‘0‘ ) ;
    return res ;
}
int ans[1000010];
int a[1000010],x;
struct is
{
    int l,r,change;
}t[1000010];
int check(int k)
{
    memset(ans,0,sizeof(ans));
    for(int i=1;i<=k;i++)
    {
        ans[t[i].l]+=t[i].change;
        ans[t[i].r+1]-=t[i].change;
    }
    int sum=0;
    for(int t=1;t<=x;t++)
    {
        sum+=ans[t];
        if(sum>a[t])
        return 0;
    }
    return 1;
}
int main()
{
    int y,z,i;
    scanf("%d%d",&x,&y);
    for(i=1;i<=x;i++)
    scanf("%d",&a[i]);
    for(i=1;i<=y;i++)
    scanf("%d%d%d",&t[i].change,&t[i].l,&t[i].r);
    int st=1;
    int en=y;
    int mid=(st+en)>>1;
    while(st<en)
    {
        mid=(st+en)>>1;
        if(check(mid))
        st=mid+1;
        else
        en=mid;
    }
    if(check(st))
    printf("0\n");
    else
    printf("-1\n%d\n",st);
    return 0;
}