Given a positive integer N, representing the count of players playing the game and an array of strings arr[], consisting of the numeric strings made up of digits from the range [‘1’, ‘N’]. Considering ith player is assigned with the string arr[i], the task is to find the winner of the game when all N players play the game optimally as per the following rules:
- Player 1 starts the game, removes the first character of the string arr[1]( 1-based indexing ), say X, and in the next turn Xth player will play the game and remove the first character of arr[X] and so on.
- The player who is not able to remove any character from the assigned string will win the game.
Examples:
Input: N = 3, arr[] = { “323”, “2”, “2” }
Output: Player 2
Explanation:
Turn 1: Removing arr[0][0] by Player 1 modifies arr[0] to “23”.
Turn 2: Removing arr[2][0] by Player 3 modifies arr[2] to “”.
Turn 3: Removing arr[1][0] by Player 2 modifies arr[1] to “”.
Turn 4: Player 2 is not able to remove any characters from arr[1].
Therefore, player 2 wins the game.Input: N = 3, arr[] = { “121”, “21”, “23123” }
Output: Player 1
Approach: The problem can be solved using Queue to remove the first character of each string efficiently. Follow the steps below to solve the problem:
- Initialize an array of Queues, say Q[], such that Q[i] stores the characters of the string arr[i].
- Traverse the array Q[] using variable i as per the rules of the game and check if the count of characters in Q[i] is 0 or not. If found to be true, then print the “Player i”.
Below is the implementation of the above approach:
C++
// C++ program to implement// the above approach#include <bits/stdc++.h>using namespace std;// Function to find the winner of a game of// repeatedly removing the first character// to empty a stringvoid find_Winner(vector<string>& arr, int N){ // Store characters of each // string of the array arr[] vector<queue<char> > Q(N); // Stores count of strings in arr[] int M = arr.size(); // Traverse the array arr[] for (int i = 0; i < M; i++) { // Stores length of current string int len = arr[i].length(); // Traverse the string for (int j = 0; j < len; j++) { // Insert arr[i][j] Q[i].push(arr[i][j] - 1); } } // 1st Player starts the game int player = 0; while (Q[player].size() > 0) { // Stores the player number // for the next turn int nextPlayer = Q[player].front() - '0'; // Remove 1st character of // current string Q[player].pop(); // Update player number for // the next turn player = nextPlayer; } cout << "Player " << (player + 1);}// Driver Codeint main(){ int N = 3; vector<string> arr = { "323", "2", "2" }; find_Winner(arr, N); return 0;} |
Java
// Java program to implement// the above approachimport java.util.*;class GFG{// Function to find the winner of a game of// repeatedly removing the first character// to empty a Stringstatic void find_Winner(String[] arr, int N){ // Store characters of each // String of the array arr[] @SuppressWarnings("unchecked") Vector<Character> [] Q = new Vector[N]; for (int i = 0; i < Q.length; i++) Q[i] = new Vector<Character>(); // Stores count of Strings in arr[] int M = arr.length; // Traverse the array arr[] for (int i = 0; i < M; i++) { // Stores length of current String int len = arr[i].length(); // Traverse the String for (int j = 0; j < len; j++) { // Insert arr[i][j] Q[i].add(arr[i].charAt(j)); } } // 1st Player starts the game int player = 0; while (Q[player].size() > 0 ) { // Stores the player number // for the next turn int nextPlayer = Q[player].get(0) - '0'-1; // Remove 1st character of // current String Q[player].remove(0); // Update player number for // the next turn player = nextPlayer; } System.out.print("Player " + (player + 1));}// Driver Codepublic static void main(String[] args){ int N = 3; String[] arr = { "323", "2", "2" }; find_Winner(arr, N);}}// This code is contributed by gauravrajput1 |
Python3
# Python3 program to implement# the above approach# Function to find the winner of a game of# repeatedly removing the first character# to empty a stringdef find_Winner(arr, N) : # Store characters of each # string of the array arr[] Q = [0]*N for i in range(N) : Q[i] = [] # Stores count of strings in arr[] M = len(arr) # Traverse the array arr[] for i in range(M) : # Stores length of current string Len = len(arr[i]) # Traverse the string for j in range(Len) : # Insert arr[i][j] Q[i].append(ord(arr[i][j]) - 1) # 1st Player starts the game player = 0 while (len(Q[player]) > 0) : # Stores the player number # for the next turn nextPlayer = Q[player][0] - ord('0') # Remove 1st character of # current string del Q[player][0] # Update player number for # the next turn player = nextPlayer print("Player", (player + 1)) N = 3arr = [ "323", "2", "2" ]find_Winner(arr, N)# This code is contributed by divyeshrabadiya07. |
C#
// C# program to implement// the above approachusing System;using System.Collections.Generic;class GFG{// Function to find the winner of a game of// repeatedly removing the first character// to empty a Stringstatic void find_Winner(String[] arr, int N){ // Store characters of each // String of the array []arr List<char> [] Q = new List<char>[N]; for(int i = 0; i < Q.Length; i++) Q[i] = new List<char>(); // Stores count of Strings in []arr int M = arr.Length; // Traverse the array []arr for(int i = 0; i < M; i++) { // Stores length of current String int len = arr[i].Length; // Traverse the String for(int j = 0; j < len; j++) { // Insert arr[i,j] Q[i].Add(arr[i][j]); } } // 1st Player starts the game int player = 0; while (Q[player].Count > 0 ) { // Stores the player number // for the next turn int nextPlayer = Q[player][0] - '0'- 1; // Remove 1st character of // current String Q[player].RemoveAt(0); // Update player number for // the next turn player = nextPlayer; } Console.Write("Player " + (player + 1));}// Driver Codepublic static void Main(String[] args){ int N = 3; String[] arr = { "323", "2", "2" }; find_Winner(arr, N);}}// This code is contributed by Rajput-Ji |
Javascript
<script>// Javascript program to implement// the above approach// Function to find the winner of a game of// repeatedly removing the first character// to empty a stringfunction find_Winner( arr, N){ // Store characters of each // string of the array arr[] var Q = Array.from(Array(N), ()=>Array()) // Stores count of strings in arr[] var M = arr.length; // Traverse the array arr[] for (var i = 0; i < M; i++) { // Stores length of current string var len = arr[i].length; // Traverse the string for (var j = 0; j < len; j++) { // Insert arr[i][j] Q[i].push(arr[i][j] - 1); } } // 1st Player starts the game var player = 0; while (Q[player].length > 0) { // Stores the player number // for the next turn var nextPlayer = Q[player][0] - '0'; // Remove 1st character of // current string Q[player].shift(); // Update player number for // the next turn player = nextPlayer; } document.write( "Player " + (player + 1));}// Driver Codevar N = 3;var arr = ["323", "2", "2"];find_Winner(arr, N);// This code is contributed by rutvik_56.</script> |
Output:
Player 2
Time Complexity: O(N * M), where M is the length of the longest string present in the array.
Auxiliary Space: O(N * M)
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