poj 1456 supermarket

貪心+並查集

 #include<stdio.h>#include<stdlib.h> struct Product {int p, t;}pro[10005];int f[10005],n;int compare(const void *m,const void *n){return (*(Product *)n).p-(*(Product *)m).p;}void init(){for (int i = 0; i <10005; i++)f[i] = i;}int find(int i){if(f[i]!=i)f[i]=find(f[i]);return f[i];}void unionSet(int m,int n){int i=find(m);int j=find(n);f[i]=j;}int main() {while (scanf("%d",&n)!=EOF){for (int i = 0; i < n; i++)scanf("%d%d",&pro[i].p,&pro[i].t);qsort(pro,n,sizeof(Product),compare);init();int sum=0;for(int i=0;i<n;i++){int temp=find(pro[i].t);if(temp!=0){sum+=pro[i].p;unionSet(temp,temp-1);}}printf("%d\n",sum);}}