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Find out the correct position of the ball after shuffling

  • Last Updated : 30 Apr, 2021

Consider a shuffle game. There are 3 glasses numbered from 1 to 3 and one ball is hidden under any one of the glass. Then any 2 of the glasses are shuffled. This operation is made 3 times.
Given an integer N ranged [1, 3] and 3 pairs of integers of the same range. The N-th glass contain the ball initially and every pair of the given integers represents the indices of the glasses needs to be shuffled. Remember the glasses are renumbered after each shuffle.
The task is to find out the index of the glass which contains the ball after all the shuffle operation.
Examples: 
 

Input: 
N = 3 
3 1 
2 1 
1 2 
Output:
Firstly the 3rd glass contain the ball. 
After the first shuffle operation (3, 1), 1st glass contain the ball. 
After the second shuffle operation (2, 1), 2nd glass contain the ball. 
After the third shuffle operation (1, 2), 1st glass contain the ball.
Input: 
N = 1 
1 3 
1 2 
2 3 
Output:
 

 

Approach: The simplest approach will be to run a loop for every shuffle operation. 
If any of the 2 glasses being shuffled contain the ball then it is obvious to change the value of N to the index of the glass being shuffled with. 
If any of the 2 shuffling glasses doesn’t contain the ball, then nothing needs to be done.
Below is the implementation of the above code: 
 

C++




// C++ implementation of the above approach
#include <bits/stdc++.h>
using namespace std;
 
const int M = 3, N = 2;
 
// Function to generate the index of the glass
// containing the ball
void getIndex(int n, int shuffle[][N])
{
    for (int i = 0; i < 3; i++) {
 
        // Checking if the glasses
        // being shuffled contain
        // the ball
 
        // Change the index
        if (shuffle[i][0] == n)
            n = shuffle[i][1];
 
        // Change the index
        else if (shuffle[i][1] == n)
            n = shuffle[i][0];
    }
 
    // Print the index
    cout << n;
}
 
// Driver's Code
int main()
{
    int n = 3;
 
    // Storing all the shuffle operation
    int shuffle[M][N] = {
        { 3, 1 },
        { 2, 1 },
        { 1, 2 }
    };
 
    getIndex(n, shuffle);
}

Java




// Java implementation of the above approach
import java.io.*;
 
class GFG
{
static int M = 3;
static int N = 2;
 
// Function to generate the index of the glass
// containing the ball
static void getIndex(int n, int shuffle[][])
{
    for (int i = 0; i < 3; i++)
    {
 
        // Checking if the glasses
        // being shuffled contain
        // the ball
 
        // Change the index
        if (shuffle[i][0] == n)
            n = shuffle[i][1];
 
        // Change the index
        else if (shuffle[i][1] == n)
            n = shuffle[i][0];
    }
 
    // Print the index
    System.out.println (n);
}
 
// Driver Code
public static void main (String[] args)
{
    int n = 3;
     
    // Storing all the shuffle operation
    int shuffle[][] = {{ 3, 1 },
                       { 2, 1 },
                       { 1, 2 }};
     
    getIndex(n, shuffle);
}
}
 
// This code is contributed by ajit.

Python3




# Python3 implementation of
# the above approach
M = 3; N = 2;
 
# Function to generate the index of
# the glass containing the ball
def getIndex(n, shuffle) :
 
    for i in range(3) :
 
        # Checking if the glasses
        # being shuffled contain
        # the ball
 
        # Change the index
        if (shuffle[i][0] == n) :
            n = shuffle[i][1];
 
        # Change the index
        elif (shuffle[i][1] == n) :
            n = shuffle[i][0];
 
    # Print the index
    print(n);
 
# Driver Code
if __name__ == "__main__" :
 
    n = 3;
 
    # Storing all the shuffle operation
    shuffle = [[ 3, 1 ],
               [ 2, 1 ],
               [ 1, 2 ]];
 
    getIndex(n, shuffle);
 
# This code is contributed by AnkitRai01

C#




// C# implementation of the above approach
using System;
     
class GFG
{
static int M = 3;
static int N = 2;
 
// Function to generate the index of
// the glass containing the ball
static void getIndex(int n, int [,]shuffle)
{
    for (int i = 0; i < 3; i++)
    {
 
        // Checking if the glasses
        // being shuffled contain
        // the ball
 
        // Change the index
        if (shuffle[i, 0] == n)
            n = shuffle[i, 1];
 
        // Change the index
        else if (shuffle[i, 1] == n)
            n = shuffle[i, 0];
    }
 
    // Print the index
    Console.WriteLine(n);
}
 
// Driver Code
public static void Main (String[] args)
{
    int n = 3;
     
    // Storing all the shuffle operation
    int [,]shuffle = {{ 3, 1 },
                      { 2, 1 },
                       { 1, 2 }};
     
    getIndex(n, shuffle);
}
}
     
// This code is contributed by Princi Singh

Javascript




<script>
// javascript implementation of the above approach
     M = 3;
     N = 2;
 
    // Function to generate the index of the glass
    // containing the ball
    function getIndex(n , shuffle) {
        for (i = 0; i < 3; i++) {
 
            // Checking if the glasses
            // being shuffled contain
            // the ball
 
            // Change the index
            if (shuffle[i][0] == n)
                n = shuffle[i][1];
 
            // Change the index
            else if (shuffle[i][1] == n)
                n = shuffle[i][0];
        }
 
        // Prvar the index
        document.write(n);
    }
 
    // Driver Code
     
        var n = 3;
 
        // Storing all the shuffle operation
        var shuffle = [ [ 3, 1 ],
                        [ 2, 1 ],
                        [ 1, 2 ] ];
 
        getIndex(n, shuffle);
 
// This code contributed by gauravrajput1
</script>
Output: 
1

 

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