2805번 나무 자르기

이분 탐색 문제이다.

https://www.acmicpc.net/problem/2805

#include <iostream>
#include <queue>
#include <stack>
#include <cstdio>
#include <vector>
#include <cstring>
#include <string>
#include <math.h>
#include <algorithm>
#include <map>
 
using namespace std;
 
int N = 0, M = 0;
 
long long Tree[1000001] = { 0, };
 
int Search(int s, int e)
{
    while (s <= e)
    {
        long long middle = (long long)(s + e) / 2;
 
        long long L = 0;
 
        for (int i = 0; i < N; i++)
        {
            if (Tree[i] - middle <= 0) continue;
 
            L += (Tree[i] - middle);
        }
 
        if (L == M) return middle;
        else if (L < M) e = middle - 1;
        else if (L > M) s = middle + 1;
    }
 
    return e;
}
 
int main(void)
{
    int MAX = -1;
 
    scanf("%d %d", &N, &M);
 
    for (int i = 0; i < N; i++)
    {
        scanf("%lld", &Tree[i]);
 
        if (MAX < Tree[i]) MAX = Tree[i];
    }
 
    printf("%d\n", Search(1, MAX));
 
    return 0;
}