In the Leetcode Rotate Image problem solution You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).
You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.
Example 1:
Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
Output: [[7,4,1],[8,5,2],[9,6,3]]
Example 2:
Input: matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]]
Output: [[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]]
Constraints:
- n == matrix.length == matrix[i].length
- 1 <= n <= 20
- -1000 <= matrix[i][j] <= 1000
Solution in C Programming
void rotate(int** matrix, int matrixSize, int* matrixColSize){
int layer = matrixSize/2;
int temp=0;
int com = *matrixColSize-1;
for(int i=0;i<layer;i++){
for (int j=i; j<com-i;j++){
temp = matrix[i][j];
matrix[i][j] = matrix[com-j][i];
matrix[com-j][i] = matrix[com-i][com-j];
matrix[com-i][com-j] = matrix[j][com-i];
matrix[j][com-i] = temp;
}
}
return matrix;
}Solution in C++ Programming
class Solution {
public:
void rotate(vector<vector<int>>& matrix) {
int n = matrix.size();
for(int i = 0;i<n;i++)
{
for(int j = 0;j<i;j++)
{
swap(matrix[i][j],matrix[j][i]);
}
}
for(int i = 0;i<n;i++)
reverse(matrix[i].begin(),matrix[i].end());
}
};Solution in Java Programming
class Solution {
public void rotate(int[][] matrix) {
int n = matrix.length;
// transpose matrix
for(int i = 0; i < n; i++){
for(int j = i; j < n; j++){
int temp = matrix[i][j];
matrix[i][j] = matrix[j][i];
matrix[j][i] = temp;
}
}
// reverse each row
for(int i = 0; i < n; i++){
for(int j = 0; j < n/2; j++){
int temp = matrix[i][j];
matrix[i][j] = matrix[i][n-j-1];
matrix[i][n-j-1] = temp;
}
}
}
}Solution in Python Programming
class Solution:
def rotate(self, matrix):
i=0
j=len(matrix)-1
n=len(matrix)
while j>i:
matrix[i],matrix[j]=matrix[j],matrix[i]
i+=1
j-=1
for i in range(n):
for j in range(i+1,n):
matrix[i][j],matrix[j][i]=matrix[j][i],matrix[i][j]Solution in C# Programming
public class Solution {
public void Rotate(int[][] matrix)
{
int top = 0;
int right = matrix[top].Length - 1;
int bottom = matrix.Length - 1;
int left = 0;
while (top <= bottom)
{
//The counter allows us to iterate through each inner layer.
int counter = 0;
for (int i = top; i < right; i++)
{
//top left becomes bottom left
//top right becomes top left
//bottom right becomes top right
//bottom left becomes bottom right
(matrix[top][left + counter], matrix[top + counter][right], matrix[bottom][right - counter], matrix[bottom - counter][left]) = (matrix[bottom - counter][left], matrix[top][left + counter], matrix[top + counter][right], matrix[bottom][right - counter]);
//Since we change them all at the same time, we just spin around the matrix with the counter.
counter++;
}
//The for loop stops once all 4 sides are changed.
//Then we go to the inner layer and do it again.
top++;
bottom--;
left++;
right--;
}
}
}Also read,