http://acm.hdu.edu.cn/showproblem.php?pid=2111
直接贪心
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include <stdio.h> #include <string.h> #include <stdlib.h> #include <math.h> struct node{ int p,m; }kk[110]; int cmp(const void*a,const void*b) { struct node*c=(struct node*)a; struct node*d=(struct node*)b; return d->p-c->p; } int main() { int v,n,i,cnt,pp; while(scanf("%d",&v),v) { scanf("%d",&n); for(i=0;i<n;i++) scanf("%d%d",&kk[i].p,&kk[i].m); qsort(kk,n,sizeof(struct node),cmp); cnt=pp=0; while(1){ pp+=kk[cnt].m*kk[cnt].p; v-=kk[cnt].m; if(v<0) { pp-=kk[cnt].m*kk[cnt].p; v+=kk[cnt].m; pp+=v*kk[cnt].p; v=0; } cnt++; if(cnt==n||v==0)break; } printf("%d\n",pp); } return 0; }