# Count Knights that can attack a given pawn in an N * N board

Given a 2D array **knights[][]** of size **N * 2**, with each row of the form **{ X, Y }** representing the coordinates of knights, and an array **pawn[]** representing the coordinates of a pawn in an **N * N** board, the task is to find the count of knights present in the board that is attacking the pawn.

**Examples:**

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Input:knights[][] = { { 0, 4 }, { 4, 5 }, { 1, 4 }, { 3, 1 } }, pawn[] = { 2, 3 }Output:2Explanation:

The knights present at coordinate { { 0, 4 }, { 3, 1 } } are attacking the pawn.

Therefore, the required output is 2.

Input:knights[][] = { { 4, 6 }, { 7, 5 }, { 5, 5 } }, pawn[] = { 6, 7 }Output:3Explanation:

The knights present at coordinate { { 4, 6 }, { 7, 5 }, { 5, 5 } } are attacking the pawn.

Therefore, the required output is 3.

**Approach:** Follow the steps given below to solve the problem

- Initialize a variable, say
**cntKnights**, to store the count of knights that are attacking the pawn. - Traverse the
**knights[][]**array using variable**i**and for every array element**knights[i]**, check if the array**{ (knights[i][0] – pawn[0]), (knights[i][1] – pawn[1]) }**is equal to either**{ 1, 2 }**or**{ 2, 1 }**or not. If found to be true, then increment the value of**cntKnights**by**1**. - Finally, print the value of
**cntKnights**.

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 count the knights that are` `// attacking the pawn in an M * M board` `int` `cntKnightsAttackPawn(` `int` `knights[][2],` ` ` `int` `pawn[], ` `int` `M)` `{` ` ` `// Stores count of knights that` ` ` `// are attacking the pawn` ` ` `int` `cntKnights = 0;` ` ` `// Traverse the knights[][] array` ` ` `for` `(` `int` `i = 0; i < M; i++) {` ` ` `// Stores absolute difference of X` ` ` `// co-ordinate of i-th knight and pawn` ` ` `int` `X = ` `abs` `(knights[i][0]` ` ` `- pawn[0]);` ` ` `// Stores absolute difference of Y` ` ` `// co-ordinate of i-th knight and pawn` ` ` `int` `Y = ` `abs` `(knights[i][1]` ` ` `- pawn[1]);` ` ` `// If X is 1 and Y is 2 or` ` ` `// X is 2 and Y is 1` ` ` `if` `((X == 1 && Y == 2)` ` ` `|| (X == 2 && Y == 1)) {` ` ` `// Update cntKnights` ` ` `cntKnights++;` ` ` `}` ` ` `}` ` ` `return` `cntKnights;` `}` `// Driver Code` `int` `main()` `{` ` ` `int` `knights[][2] = { { 0, 4 }, { 4, 5 },` ` ` `{ 1, 4 }, { 3, 1 } };` ` ` `int` `pawn[] = { 2, 3 };` ` ` `// Stores total count of knights` ` ` `int` `M = ` `sizeof` `(knights)` ` ` `/ ` `sizeof` `(knights[0]);` ` ` `cout << cntKnightsAttackPawn(` ` ` `knights, pawn, M);` ` ` `return` `0;` `}` |

## Java

`// Java program to implement` `// the above approach` `import` `java.io.*;` `import` `java.lang.Math;` `class` `GFG{` `// Function to count the knights that are` `// attacking the pawn in an M * M board` `static` `int` `cntKnightsAttackPawn(` `int` `knights[][],` ` ` `int` `pawn[], ` `int` `M)` `{` ` ` ` ` `// Stores count of knights that` ` ` `// are attacking the pawn` ` ` `int` `cntKnights = ` `0` `;` ` ` ` ` `// Traverse the knights[][] array` ` ` `for` `(` `int` `i = ` `0` `; i < M; i++)` ` ` `{` ` ` ` ` `// Stores absolute difference of X` ` ` `// co-ordinate of i-th knight and pawn` ` ` `int` `X = Math.abs(knights[i][` `0` `] - pawn[` `0` `]);` ` ` ` ` `// Stores absolute difference of Y` ` ` `// co-ordinate of i-th knight and pawn` ` ` `int` `Y = Math.abs(knights[i][` `1` `] - pawn[` `1` `]);` ` ` ` ` `// If X is 1 and Y is 2 or` ` ` `// X is 2 and Y is 1` ` ` `if` `((X == ` `1` `&& Y == ` `2` `) ||` ` ` `(X == ` `2` `&& Y == ` `1` `))` ` ` `{` ` ` ` ` `// Update cntKnights` ` ` `cntKnights++;` ` ` `}` ` ` `}` ` ` `return` `cntKnights;` `}` `// Driver code` `public` `static` `void` `main(String[] args)` `{` ` ` `int` `[][] knights = { { ` `0` `, ` `4` `}, { ` `4` `, ` `5` `},` ` ` `{ ` `1` `, ` `4` `}, { ` `3` `, ` `1` `} };` ` ` ` ` `int` `[] pawn = ` `new` `int` `[]{` `2` `, ` `3` `};` ` ` ` ` `// Stores total count of knights` ` ` `int` `M = knights.length;` ` ` ` ` `System.out.println(cntKnightsAttackPawn(` ` ` `knights, pawn, M));` `}` `}` `// This code is contributed by vandanakillari54935` |

## Python3

`# Python program to implement` `# the above approach` `# Function to count the knights that are` `# attacking the pawn in an M * M board` `def` `cntKnightsAttackPawn(knights, pawn, M):` ` ` ` ` `# Stores count of knights that` ` ` `# are attacking the pawn` ` ` `cntKnights ` `=` `0` `;` ` ` `# Traverse the knights array` ` ` `for` `i ` `in` `range` `(M):` ` ` `# Stores absolute difference of X` ` ` `# co-ordinate of i-th knight and pawn` ` ` `X ` `=` `abs` `(knights[i][` `0` `] ` `-` `pawn[` `0` `]);` ` ` `# Stores absolute difference of Y` ` ` `# co-ordinate of i-th knight and pawn` ` ` `Y ` `=` `abs` `(knights[i][` `1` `] ` `-` `pawn[` `1` `]);` ` ` `# If X is 1 and Y is 2 or` ` ` `# X is 2 and Y is 1` ` ` `if` `((X ` `=` `=` `1` `and` `Y ` `=` `=` `2` `) ` `or` `(X ` `=` `=` `2` `and` `Y ` `=` `=` `1` `)):` ` ` ` ` `# Update cntKnights` ` ` `cntKnights ` `+` `=` `1` `;` ` ` `return` `cntKnights;` `# Driver code` `if` `__name__ ` `=` `=` `'__main__'` `:` ` ` `knights ` `=` `[[` `0` `, ` `4` `], [` `4` `, ` `5` `], [` `1` `, ` `4` `], [` `3` `, ` `1` `]];` ` ` `pawn ` `=` `[` `2` `, ` `3` `];` ` ` `# Stores total count of knights` ` ` `M ` `=` `len` `(knights);` ` ` `print` `(cntKnightsAttackPawn(knights, pawn, M));` `# This code is contributed by Amit Katiyar` |

## C#

`// C# program to implement` `// the above approach` `using` `System;` `class` `GFG` `{` ` ` `// Function to count the knights that are` ` ` `// attacking the pawn in an M * M board` ` ` `static` `int` `cntKnightsAttackPawn(` `int` `[,] knights, ` `int` `[] pawn, ` `int` `M)` ` ` `{` ` ` `// Stores count of knights that` ` ` `// are attacking the pawn` ` ` `int` `cntKnights = 0;` ` ` `// Traverse the knights[][] array` ` ` `for` `(` `int` `i = 0; i < M; i++) {` ` ` `// Stores absolute difference of X` ` ` `// co-ordinate of i-th knight and pawn` ` ` `int` `X = Math.Abs(knights[i, 0] - pawn[0]);` ` ` `// Stores absolute difference of Y` ` ` `// co-ordinate of i-th knight and pawn` ` ` `int` `Y = Math.Abs(knights[i, 1] - pawn[1]);` ` ` `// If X is 1 and Y is 2 or` ` ` `// X is 2 and Y is 1` ` ` `if` `((X == 1 && Y == 2)` ` ` `|| (X == 2 && Y == 1)) {` ` ` `// Update cntKnights` ` ` `cntKnights++;` ` ` `}` ` ` `}` ` ` `return` `cntKnights;` ` ` `}` ` ` `// Driver code` ` ` `static` `void` `Main()` ` ` `{` ` ` `int` `[,] knights = {{ 0, 4 }, { 4, 5 }, { 1, 4 }, { 3, 1 }};` ` ` `int` `[] pawn = {2, 3};` ` ` `// Stores total count of knights` ` ` `int` `M = knights.GetLength(0);` ` ` `Console.WriteLine(cntKnightsAttackPawn(knights, pawn, M));` ` ` `}` `}` `// This code is contributed by divyeshrabadiya07` |

## Javascript

`<script>` `// javascript program for the above approach` `// Function to count the knights that are` `// attacking the pawn in an M * M board` `function` `cntKnightsAttackPawn(knights,` ` ` `pawn, M)` `{` ` ` ` ` `// Stores count of knights that` ` ` `// are attacking the pawn` ` ` `let cntKnights = 0;` ` ` ` ` `// Traverse the knights[][] array` ` ` `for` `(let i = 0; i < M; i++)` ` ` `{` ` ` ` ` `// Stores absolute difference of X` ` ` `// co-ordinate of i-th knight and pawn` ` ` `let X = Math.abs(knights[i][0] - pawn[0]);` ` ` ` ` `// Stores absolute difference of Y` ` ` `// co-ordinate of i-th knight and pawn` ` ` `let Y = Math.abs(knights[i][1] - pawn[1]);` ` ` ` ` `// If X is 1 and Y is 2 or` ` ` `// X is 2 and Y is 1` ` ` `if` `((X == 1 && Y == 2) ||` ` ` `(X == 2 && Y == 1))` ` ` `{` ` ` ` ` `// Update cntKnights` ` ` `cntKnights++;` ` ` `}` ` ` `}` ` ` `return` `cntKnights;` `}` `// Driver Code` ` ` ` ` `let knights = [[ 0, 4 ], [ 4, 5 ],` ` ` `[ 1, 4 ], [ 3, 1 ]];` ` ` ` ` `let pawn = [2, 3];` ` ` ` ` `// Stores total count of knights` ` ` `let M = knights.length;` ` ` ` ` `document.write(cntKnightsAttackPawn(` ` ` `knights, pawn, M));` `</script>` |

**Output**

2

**Time Complexity:** O(M), where **M** is the total count number of knights**Auxiliary Space:** O(1)