Rotate Matrix
1.7 Rotate Matrix: Given an image represented by an NxN matrix, where each pixel in the image is 4 bytes, write a method to rotate the image by 90 degrees. Can you do this in place?
#include <iostream>
#include <string>
using namespace std;
void printMatrix(size_t N, int (*matrix)[3]) {
for (int i = 0; i < N; i++) {
for (int j = 0; j < N; j++) {
cout << matrix[i][j] << " ";
}
cout << endl;
}
cout << endl;
}
// not in place
// O(?) space
// O(N) algorithm
void rotateMatrix(size_t N, int (*matrix)[3]) {
printMatrix(3, matrix);
int newMatrix[3][3];
for (int i = 0; i < N; i++) {
for (int j = 0; j < N; j++) {
// for each row in matrix add to last column new matrix
newMatrix[j][N - i - 1] = matrix[i][j];
}
}
printMatrix(3, newMatrix);
}
int main()
{
/*
1 2 3 7 8 9
4 5 6 -> 8 5 2
7 8 9 9 6 3
*/
int matrix[3][3] = {
{1,2,3},
{4,5,6},
{7,8,9}
};
rotateMatrix(3, matrix);
}
Last modified 3yr ago