[실2] 2805 - 나무 자르기

#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

#pragma region 입출력 속도향상

#define FAST_IO() \
{\
	ios::sync_with_stdio(false);\
	cin.tie(NULL); \
	cout.tie(NULL); \
}\

#pragma endregion

vector<long> v;

int main()
{
	FAST_IO();

	long n, m;
	cin >> n >> m;
	v.resize(n);

	for (int i = 0; i < n; i++)
		cin >> v[i];

	sort(v.begin(), v.end());
	long l = 0, r = v[n - 1];
	long res = 0;

	while (l <= r)
	{
		long mid = (l + r) / 2;
		long sum = 0;

		for (int i = 0; i < n; i++)
		{
			if (v[i] > mid)
				sum += v[i] - mid;
		}
		if (sum >= m)
		{
			res = mid;
			l = mid + 1;
		}
		else
			r = mid - 1;
	}
	cout << res;
	return 0;
}