BOJ1654 랜선 자르기 (매개변수 탐색)

https://www.acmicpc.net/problem/1654

1654번: 랜선 자르기

 

import java.util.*;
import java.io.*;

public class Main
{
    
    public static long[] lansun;
    public static int n;
    public static int m;
    
    
    public static long search(){
        long l = 0l;
        long r = 1l<<32 -1 ;
        long length = 0;
        while(l<=r){
            long mid = (l+r)/2;
            int count = 0;
            for(int i=0; i<n;i++){
                count+= lansun[i]/mid;
            }
            
            if(count>=m){
                l=mid+1;
                length=mid;
                
            }else{
                r=mid-1;
            }
            
        }
        
        return length;
    }
    
    
    
	public static void main(String[] args) throws IOException {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    
	    String[] input1 = br.readLine().split(" ");
	    
	    n = Integer.valueOf(input1[0]);
	    m = Integer.valueOf(input1[1]);
		lansun = new long[n];
		
		for(int i=0; i<n;i++){
		    lansun[i] = Long.valueOf(br.readLine());
		}
		
		long ans = search();
		
		System.out.println(ans);
		
		
		
		
	}
}

import java.util.Scanner;

class Main
{
    static int calculateCount(int[] lengths, long cutLength) {
        int cnt = 0;
        for (int l : lengths)
            cnt += l / cutLength;
        return cnt;
    }

    public static void main (String[] args) {
        Scanner sc = new Scanner(System.in);

        int K = sc.nextInt();
        int N = sc.nextInt();
        int[] len = new int[K];
        for (int i = 0; i < K; i++)
            len[i] = sc.nextInt();

        long l = 1, r = (1L << 31) - 1, ans = -1;
        while (l <= r) {
            long m = l + (r - l) / 2;
            if (calculateCount(len, m) >= N) {
                ans = m;
                l = m + 1;
            }
            else r = m - 1;
        }
        System.out.println(ans);
    }
}