poj 1456 Supermarket 贪心 并查集优化

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#include<queue>
#define maxn 10015
using namespace std;
int n;
struct node{
int mo,ti;
}no[maxn];
int fa[maxn];
int getFa(int pre)
{
if(pre == fa[pre])return pre;
fa[pre] = getFa(fa[pre]);
return fa[pre];
}
bool cmp(node no1,node no2)
{
return no1.mo>no2.mo;
}
int main()
{
while(scanf("%d",&n)!=EOF)
{
int time = -1;
for(int i=1;i<=n;i++){ scanf("%d %d",&no[i].mo,&no[i].ti); time = max(time,no[i].ti);}
sort(no+1,no+n+1,cmp);
for(int i=0;i<=time;i++)fa[i] = i;
int sum = 0;
for(int i=1;i<=n;i++)
{
int pre = getFa(no[i].ti);
if(pre)
{
fa[pre] = pre-1;
sum+=no[i].mo;
}
}
printf("%d\n",sum);
}
return 0;
}