【hoj】1604 cable master

標籤：二分尋找   hoj   algorithm   

簡單，二分法，但是在oj上交的時候會有精度的限制，所以只能把數擴得大一點，而且在擴的時候為防止尾數會自動產生一些非零數，所以還是自己吧擴到的位置設定為0，還有輸出時因為%.2lf會自己有4設5入，所以可以自己算出小數點後兩位的數值，在輸出，保證要求的精度

#include <iostream>#include <stdio.h>#include <algorithm>#define MAX 10010using namespace std;long long input[MAX];int m,n;bool cmp(int a,int b){    return a<b;}bool judge(int mid){    int x = 0;    for(int i = 0;i < n;i++){        x += input[i] / mid;    }    if(x >= m)        return true;    else        return false;}int main(){//#ifndef ONLINE_JUDGE  //  freopen("in.txt","r",stdin);//#endif    long long high,low,mid,res;    double a;    while(cin>>n>>m){        high = 0;        low = 0;        for(int i = 0;i < n;i++){            cin>>a;            input[i] = (a+1e-8)*10000;            high = high > input[i]?high : input[i];        }        sort(input,input+n,cmp);        res = 0;        low = 10000/100;        while(low <= high){            mid = (low+high)/2;            if(judge(mid)){                res = mid;                low = mid+1;            }            else                high = mid-1;        }        int th = res/10000;        int hu = (res - th * 10000)/1000;        int te = (res - th * 10000 - hu * 1000)/100;      printf("%d.%d%d\n",th,hu,te);    }}