poj 2459 Feed Accounting

#include<iostream>using namespace std;#define MAX_size 2005int cow[MAX_size];int main(){  int c,f1,f2,d;  int i,j;  int a,b;     cin>>c>>f1>>f2>>d;  memset(cow,0,sizeof(cow));  for(i = 0;i<c;i++)  {    cin>>a>>b;    for(j = a;j<=b;j++)    {      cow[j]++;    }  }  j = d;  int pay = f1 - f2;  while(pay!=0)    pay-=cow[j--];  cout<<j+1<<endl;  return 0;}