백준 2805번 나무자르기

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

#include <cstdio>
#include <cmath>
#include <algorithm>
#pragma warning(disable:4996)
#define MAX 1000000
using namespace std;
long long N, M;
long long tree[MAX + 1];
int main()
{
	scanf("%lld %lld", &N, &M);
	for (int i = 0; i < N; i++)
		scanf("%lld", &tree[i]);
	std::sort(tree, tree + N);
	long long left = 1;
	long long right = tree[N - 1];
	long long result = 0;
	while (left <= right)
	{
		long long mid = left + (right - left) / 2;
		long long len = 0;
		for (int i = 0; i < N; i++)
		{
			if (tree[i] > mid)
				len += ( tree[i] - mid );
		}
		if (len >= M)
		{
			if (result < mid)
				result = mid;
			left = mid + 1;
		}
		else
			right = mid - 1;
	}
	printf("%lld\n", result);
	return 0;
}ㅂ