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Check if all enemies are killed with bombs placed in a matrix
  • Difficulty Level : Basic
  • Last Updated : 03 Feb, 2021

Given a Character matrix as input, the task is to check whether all the enemies are killed or not based on below conditions: 

1. The matrix can contain 3 characters 
X –> Denotes the War area. 
B –> Denotes the bomb. 
E –> Denotes the Enemies.
2. Bomb ‘B’ can blast in only horizontal and vertical directions from one end to another. 
3. If all enemies are killed by the present bombs, print Yes, else print No 
 

Examples:  

Input: matrix =
XXEX
XBXX
XEXX
XXBX 
Output: Yes

Input: matrix =
XXEX
XBXX
XEXX
XXXX
Output: No

Approach: The given problem can be solved by the following approach:  

  1. Get the character Matrix 
  2. Traverse to find all bomb indices in the matrix 
  3. For each bomb found, see if any enemy is present in its vertical or horizontal direction. If present kill that enemy, i.e. change E to X 
  4. After all traversals, check if any enemy is present in the matrix or not. 
  5. Print Yes if all enemies are killed, else print No. 

Implementation: 

C++




// C++ program to kill all enemies
 
#include <iostream>
using namespace std;
 
// Function to find Enemies killed or not
int Kill_Enemy(string s[], int row, int col)
{
 
    int i, j, x, y;
 
    // Loop to evaluate the Bomb
    for (i = 0; i < row; i++) {
        for (j = 0; j < col; j++) {
 
            // Check if this index is a bomb
            if (s[i][j] == 'B') {
 
                // Kill all enemies
                // in horizontal direction
                for (x = 0; x < row; x++) {
                    if (s[x][j] != 'B')
                        s[x][j] = 'X';
                }
 
                // Kill all enemies
                // in vertical direction
                for (y = 0; y < col; y++) {
                    if (s[i][y] != 'B')
                        s[i][y] = 'X';
                }
            }
        }
    }
    // All bombs have been found
 
    // Check if any enemy is still present
    for (i = 0; i < row; i++) {
        for (j = 0; j < col; j++) {
 
            if (s[i][j] == 'E')
 
                // Since an enemy is present
                // Return 0 denoting No as output
                return 0;
        }
    }
 
    // Since all enemies are killed
    // Return 1 denoting Yes as output
    return 1;
}
 
// Driver Code
int main(int argc, char** argv)
{
    // Get the input matrix
    string s[] = { "XXEX",
                   "XBXX",
                   "XEXX",
                   "XXBX" };
 
    // Calculate Rows and columns of the string
    int row = sizeof(s) / sizeof(s[0]),
        col = s[0].length();
 
    // Check if all enemies will be killed or not
    if (Kill_Enemy(s, row, col) == 1)
        cout << "Yes";
    else
        cout << "No";
 
    return 0;
}

Java




// Java program to kill all enemies
class GFG
{
 
// Function to find Enemies killed or not
static int Kill_Enemy(char [][]s, int row, int col)
{
 
    int i, j, x, y;
 
    // Loop to evaluate the Bomb
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
 
            // Check if this index is a bomb
            if (s[i][j] == 'B')
            {
 
                // Kill all enemies
                // in horizontal direction
                for (x = 0; x < row; x++)
                {
                    if (s[x][j] != 'B')
                        s[x][j] = 'X';
                }
 
                // Kill all enemies
                // in vertical direction
                for (y = 0; y < col; y++)
                {
                    if (s[i][y] != 'B')
                        s[i][y] = 'X';
                }
            }
        }
    }
     
    // All bombs have been found
 
    // Check if any enemy is still present
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
 
            if (s[i][j] == 'E')
 
                // Since an enemy is present
                // Return 0 denoting No as output
                return 0;
        }
    }
 
    // Since all enemies are killed
    // Return 1 denoting Yes as output
    return 1;
}
 
// Driver Code
public static void main(String[] args)
{
    // Get the input matrix
    char [][]s = { "XXEX".toCharArray(),
                "XBXX".toCharArray(),
                "XEXX".toCharArray(),
                "XXBX".toCharArray() };
 
    // Calculate Rows and columns of the String
    int row = s.length,
        col = s[0].length;
 
    // Check if all enemies will be killed or not
    if (Kill_Enemy(s, row, col) == 1)
        System.out.print("Yes");
    else
        System.out.print("No");
}
}
 
// This code is contributed by Rajput-Ji

Python3




# Python3 program to kill all enemies
 
# Function to find Enemies killed or not
def Kill_Enemy(s, row, col):
    i, j, x, y = 0, 0, 0, 0;
 
    # Loop to evaluate the Bomb
    for i in range(row):
        for j in range(col):
             
            # Check if this index is a bomb
            if (s[i][j] == 'B'):
 
                # Kill all enemies
                # in horizontal direction
                for x in range(row):
                    if (s[x][j] != 'B'):
                        s[x][j] = 'X';
 
                # Kill all enemies
                # in vertical direction
                for y in range(col):
                    if (s[i][y] != 'B'):
                        s[i][y] = 'X';
 
    # All bombs have been found
 
    # Check if any enemy is still present
    for i in range(row):
        for j in range(col):
 
            if (s[i][j] == 'E'):
 
                # Since an enemy is present
                # Return 0 denoting No as output
                return 0;
 
    # Since all enemies are killed
    # Return 1 denoting Yes as output
    return 1;
 
# Driver Code
if __name__ == '__main__':
 
    # Get the input matrix
    s = [['X','X','E','X'],
        ['X','B','X','X'],
        ['X','E','X','X'],
        ['X','X','B','X']]
 
    # Calculate Rows and columns of the String
    row = len(s);
    col = len(s[0]);
 
    # Check if all enemies will be killed or not
    if (Kill_Enemy(s, row, col) == 1):
        print("Yes");
    else:
        print("No");
 
# This code is contributed by Rajput-Ji

C#




// C# program to kill all enemies
using System;
 
class GFG
{
 
// Function to find Enemies killed or not
static int Kill_Enemy(char [,]s,
                      int row, int col)
{
    int i, j, x, y;
 
    // Loop to evaluate the Bomb
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
 
            // Check if this index is a bomb
            if (s[i, j] == 'B')
            {
 
                // Kill all enemies
                // in horizontal direction
                for (x = 0; x < row; x++)
                {
                    if (s[x, j] != 'B')
                        s[x, j] = 'X';
                }
 
                // Kill all enemies
                // in vertical direction
                for (y = 0; y < col; y++)
                {
                    if (s[i, y] != 'B')
                        s[i, y] = 'X';
                }
            }
        }
    }
     
    // All bombs have been found
 
    // Check if any enemy is still present
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
 
            if (s[i, j] == 'E')
 
                // Since an enemy is present
                // Return 0 denoting No as output
                return 0;
        }
    }
 
    // Since all enemies are killed
    // Return 1 denoting Yes as output
    return 1;
}
 
// Driver Code
public static void Main(String[] args)
{
    // Get the input matrix
    char [,]s = {{'X', 'B', 'X', 'X'},
                 {'X', 'E', 'X', 'X'},
                 {'X', 'X', 'B', 'X'}};
     
    // Calculate Rows and columns of the String
    int row = s.GetLength(0),
        col = s.GetLength(1);
 
    // Check if all enemies will be killed or not
    if (Kill_Enemy(s, row, col) == 1)
        Console.Write("Yes");
    else
        Console.Write("No");
}
}
 
// This code is contributed by Rajput-Ji
Output: 
Yes

 

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