[백준 1654] 랜선 자르기 (Binary Search) (C/C++) (★)

#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <string>
#include <string.h>
#include <math.h>
#include <map>
#include <vector>
using namespace std;
 
int K, N;
long long Max;
long long lan[10010];
 
int cal(int mid)
{
    int cnt = 0;
    
    for(int i = 1; i <= K; i++)
    {
        cnt += lan[i] / mid;
    }
    
    return cnt;
}
 
int main(void)
{
//    freopen("B1654_input.txt", "r", stdin);
    
    cin >> K >> N;
    
    for(int i = 1; i <= K; i++)
    {
        cin >> lan[i];
    }
    
    sort(lan+1, lan+K+1);
    
    long long left = 1;
    long long right = lan[K];
    
    while(left <= right)
    {
        // 랜선의 길이 
        long long mid = (left + right) / 2;
        
        // 나눈 랜선의 총 갯수 
        int divideCnt = cal(mid);
        
        if(divideCnt >= N)
        {
            left = mid+1;
            
            if(mid > Max)
            {
                Max = mid;
            }
        }
        else
        {
            right = mid-1;
        }
    }
    
    cout << Max;
    
    return 0;
}