matrix_rotation.cpp

#include<bits/stdc++.h> 
#define MAX 100 
using namespace std; 

void fillSpiral(int mat[][MAX], int m, int n, int temp[]) 
{ 
	int i, k = 0, l = 0; 

	int tIdx = 0; 
	while (k < m && l < n) 
	{ 
		
		for (int i = l; i < n; ++i) 
			mat[k][i] = temp[tIdx++]; 
		k++; 

		
		for (int i = k; i < m; ++i) 
			mat[i][n-1] = temp[tIdx++]; 
		n--; 

		
		if (k < m) 
		{ 
			for (int i = n-1; i >= l; --i) 
				mat[m-1][i] = temp[tIdx++]; 
			m--; 
		} 

		
		if (l < n) 
		{ 
			for (int i = m-1; i >= k; --i) 
				mat[i][l] = temp[tIdx++]; 
			l++; 
		} 
	} 
} 

void spiralRotate(int mat[][MAX], int M, int N, int k) 
{ 
	 
	int temp[M*N]; 

	int m = M, n = N, s = 0, l = 0; 

	int *start = temp;  
	int tIdx = 0;
	while (s < m && l < n) 
	{ 
		
		int *end = start; 

		
		for (int i = l; i < n; ++i) 
		{ 
			temp[tIdx++] = mat[s][i]; 
			end++; 
		} 
		s++;  
		for (int i = s; i < m; ++i) 
		{ 
			temp[tIdx++] = mat[i][n-1]; 
			end++; 
		} 
		n--; 

		if (s < m) 
		{ 
			for (int i = n-1; i >= l; --i) 
			{ 
				temp[tIdx++] = mat[m-1][i]; 
				end++; 
			} 
			m--; 
		} 

		if (l < n) 
		{ 
			for (int i = m-1; i >= s; --i) 
			{ 
				temp[tIdx++] = mat[i][l]; 
				end++; 
			} 
			l++; 
		} 

		if (end-start > k) 
		{ 
			reverse(start, start+k); 
			reverse(start+k, end); 
			reverse(start, end); 

			start = end; 
		} 
		else 
			break; 
	} 

	fillSpiral(mat, M, N, temp); 
} 

int main() 
{ 
	int M = 4, N = 4, k = 3; 
	int mat[][MAX]= {{1, 2, 3, 4}, 
					{5, 6, 7, 8}, 
					{9, 10, 11, 12}, 
					{13, 14, 15, 16} }; 

	spiralRotate(mat, M, N, k); 

	for (int i=0; i<M; i++) 
	{ 
		for (int j=0; j<N; j++) 
			cout << mat[i][j] << " "; 
		cout << endl; 
	} 
	return 0; 
}