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Rotate matrix by 90 degree #2316

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Sep 20, 2021
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Rotate matrix by 90 degree #2316

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71 changes: 71 additions & 0 deletions Others/RotateMatriceBy90Degree.java
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Original file line number Diff line number Diff line change
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package Others;

/**
* Given a matrix of size n x n
* We have to rotate this matrix by 90 Degree
* Here is the algorithm for this problem .
*
*/

import java.util.*;

class Rotate_by_90_degree {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int t = sc.nextInt();

while (t-- > 0) {
int n = sc.nextInt();
int[][] arr = new int[n][n];

for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++)
arr[i][j] = sc.nextInt();

Rotate g = new Rotate();
g.rotate(arr);
printMatrix(arr);

}
sc.close();
}

static void printMatrix(int arr[][]) {
for (int i = 0; i < arr.length; i++) {
for (int j = 0; j < arr[0].length; j++)
System.out.print(arr[i][j] + " ");
System.out.println("");
}
}
}

/**
* Class containing the algo to roate matrix by 90 degree
*/

class Rotate {
static void rotate(int a[][]) {
int n = a.length;
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (i > j) {
int temp = a[i][j];
a[i][j] = a[j][i];
a[j][i] = temp;
}
}
}
int i = 0, k = n - 1;
while (i < k) {
for (int j = 0; j < n; j++) {
int temp = a[i][j];
a[i][j] = a[k][j];
a[k][j] = temp;
}

i++;
k--;
}

}
}