[백준 2869] 달팽이는 올라가고 싶다 (Binary Search) (C/C++)

#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <string>
#include <string.h>
#include <math.h>
#include <unordered_map>
#include <vector>
using namespace std;
 
long long A, B, V;
 
int main(void)
{
//    freopen("B2869_input.txt", "r", stdin);
 
    cin >> A >> B >> V;
    
    long long left = 1;
    long long right = V;
    long long Min = 1111111111;
    
    while(left <= right)
    {
        // 날짜 
        long long mid = (left + right) / 2;
 
        if(A * mid - B * (mid-1) >= V)
        {
            
            if(mid < Min)
            {
                Min = mid;
            }
            
            right = mid-1;
        }
        else if(A * mid - B * (mid-1) < V)
        {
            left = mid+1;
        }
    }
    
    cout << Min;
 
    return 0;
}