hdu2111 Saving HDU (贪心)

#include <stdio.h>#include <stdlib.h>struct node{int pi,mi;}bao[102];int cmp(const void *x,const void *y){return (*(struct node *)y).pi-(*(struct node *)x).pi;}int main(){int n,v,i,sum;while(scanf("%d",&v)&&v){sum=0;scanf("%d",&n);for(i=0;i<n;i++)scanf("%d %d",&bao[i].pi,&bao[i].mi);qsort(bao,n,sizeof(bao[0]),cmp);for (i=0;i<n;i++){if(v-bao[i].mi>0){sum+=bao[i].mi*bao[i].pi;v-=bao[i].mi;}else{sum+=v*bao[i].pi;break;}}printf("%d\n",sum);}return 0;}