44 lines
798 B
C++
44 lines
798 B
C++
#include<stdio.h>
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#include<algorithm>
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using namespace std;
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struct rice
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{
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int p;
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int h;
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};
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int cmp(rice x,rice y)
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{return x.p<y.p;}
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int main()
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{
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int c,n,m,i;
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double sum;
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rice st[1001];
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scanf("%d",&c);
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while(c--)
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{
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scanf("%d%d",&n,&m);
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sum=0;
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for(i=0;i<m;i++)
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{
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scanf("%d",&st[i].p);
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scanf("%d",&st[i].h);
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}
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sort(st,st+m,cmp);
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for(i=0;i<m;i++)
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{
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if(n>st[i].p*st[i].h)
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{
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sum+=st[i].h;
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n-=st[i].h*st[i].p;
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}
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else
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{
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sum+=n*1.0/st[i].p;
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break;
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}
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}
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printf("%.2lf\n",sum);
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}
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return 0;
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}
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