如果某人在某些天后离开，则完成任务所需的总天数

假设人A花了几天的时间做某件工作，而人B花了b天的时间做同样的工作。如果A和B一起开始工作，并且在工作完成前n天，则A离开工作。查找完成工作所需的总天数。

例子：

Input: a = 10, b = 20, n = 5 
Output: 10

Input: a = 5, b = 15, n = 3 
Output: 6  

方法：设D为完成工作的总天数。 A和B一起工作了D – n天。所以，

(D – n) * (1/a + 1/b) + (n) * (1/b) = 1 
D * (1/a + 1/b) – (n/a) – (n/b) + (n/b) = 1 
D * (1/a + 1/b) = (n + a) / a 
D = b * (n + a) / (a + b) 

下面是上述方法的实现：

C++

// C++ implementation of the approach
#include 
using namespace std;
 
// Function to return the
// number of days required
int numberOfDays(int a, int b, int n)
{
    int Days = b * (n + a) / (a + b);
 
    return Days;
}
 
// Driver code
int main()
{
    int a = 10, b = 20, n = 5;
 
    cout << numberOfDays(a, b, n);
 
    return 0;
}

Java

// Java implementation of the approach
import java.io.*;
 
class GFG
{
     
// Function to return the
// number of days required
static int numberOfDays(int a, int b, int n)
{
    int Days = b * (n + a) / (a + b);
 
    return Days;
}
 
// Driver code
public static void main (String[] args)
{
 
    int a = 10, b = 20, n = 5;
    System.out.println (numberOfDays(a, b, n));
 
}
}
 
// This code is contributed by jit_t

Python3

# Python3 implementation of the approach
  
# Function to return the
# number of days required
def numberOfDays(a, b, n):
 
    Days = b * (n + a) // (a + b)
  
    return Days
 
# Driver code
if __name__ == "__main__" :
 
    a = 10
    b = 20
    n = 5
  
    print(numberOfDays(a, b, n))
 
# This code is contributed by rrrtnx

C#

// C# implementation of the approach
using System;
 
class GFG
{
     
    // Function to return the
    // number of days required
    static int numberOfDays(int a, int b, int n)
    {
        int Days = b * (n + a) / (a + b);
     
        return Days;
    }
     
    // Driver code
    public static void Main ()
    {
     
        int a = 10, b = 20, n = 5;
        Console.WriteLine(numberOfDays(a, b, n));
     
    }
}
 
// This code is contributed by AnkitRai01

Javascript

// javascript implementation of the approach
 
    // Function to return the
    // number of days required
    function numberOfDays(a , b , n)
    {
        var Days = b * (n + a) / (a + b);
        return Days;
    }
 
    // Driver code
    var a = 10, b = 20, n = 5;
    document.write(numberOfDays(a, b, n));
 
// This code is contributed by Rajput-Ji

输出：

10

时间复杂度： O(1)

辅助空间： O(1)