[C++] 2805 - 나무 자르기

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

2805번: 나무 자르기

 

 

 

 

#include<bits/stdc++.h>
 
using namespace std;
 
int A[1000005];
int N, M;
 
int MIN, MAX;
 
int bisearch()
{
    int left = 0;
    int right = INT_MAX;
    int mid;
 
    unsigned long long sum;
    int save;
    while(left <= right)
    {
        sum = 0;
        mid = (left+right)/2;
        for(int i = 0; i < N; ++i)
            if(A[i] - mid > 0)
                sum += A[i]-mid;
        
        if(sum == M)
            return mid;
        else if(sum > M)
        {
            save = mid;
            left = mid+1;
        }
        else if(sum < M)
            right = mid-1;
    }
 
    return save;
}
 
int main(void)
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
 
    cin >> N >> M;
    for(int i = 0; i < N; ++i)
        cin >> A[i];
 
    sort(A, A+N);
 
    cout << bisearch() << endl;
 
    return 0;
}