POJ 2431 Expedition (贪心+优先队列)

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <stdlib.h>
#include <math.h>
#include <ctype.h>
#include <queue>
#include <map>
#include <set>
#include <algorithm>

using namespace std;
struct node
{
int d, p;
}stop[11000];
int cmp(node x, node y)
{
return x.d<y.d;
}
int main()
{
int n, i, j, l, p, flag=0, s, cnt;
scanf("%d",&n);
priority_queue<int>q;
for(i=0;i<n;i++)
{
scanf("%d%d",&stop[i].d,&stop[i].p);
}
scanf("%d%d",&l,&p);
for(i=0;i<n;i++)
{
stop[i].d=l-stop[i].d;
}
stop
.d=l;
stop
.p=0;
sort(stop,stop+n+1,cmp);
cnt=0;
for(i=0;i<=n;i++)
{
if(stop[i].d<0) continue ;
if(p<stop[i].d)
{
while(!q.empty()&&p<stop[i].d)
{
p+=q.top();
q.pop();
cnt++;
}
if(p<stop[i].d)
{
flag=1;
break;
}
}
q.push(stop[i].p);
}
if(flag) puts("-1");
else
printf("%d\n",cnt);
return 0;
}