……
精度各種鍋
轉了int再判終於對了
還有cin cout 被卡
傷心

#include <cstdio>

using namespace std;

const int MAXN=10011;

double input;
int N, K;
int Num[MAXN];
int Left, Right, Mid;

bool Test(int k){
    int c=0;
    for(int i=1;i<=N;++i){
        c+=Num[i]/k;
    }
    return c>=K;
}

int main(){
    
    while(scanf("%d%d", &N, &K)!=EOF){
        for(int i=1;i<=N;++i){
            scanf("%lf", &input);
            Num[i]=(int)(input*100.0);
        }
        Left=0;Right=0;
        for(int i=1;i<=N;++i)   if(Num[i]>Right)    Right=Num[i];
        while(Left<Right){
            Mid=(Left+Right)>>1;
            if(Test(Mid+1)) Left=Mid+1;
            else    Right=Mid;
        }
        Mid=(Left+Right)>>1;
        printf("%d.%d%d\n", Mid/100, (Mid/10)%10, Mid%10);
    }
    
    return 0;
}
 

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