Matrix_rotation_90degree.cpp

/*
This is C++ code for: Rotate the given matrix by 90 degree to right 
For example:
          1 2 3                7 4 1
          4 5 6     ====>      8 5 2
          7 8 9                9 6 3
*/
#include <bits/stdc++.h>
using namespace std;

void rotate(vector<vector<int>> &ans)
{
    int n = ans.size();
    for (int i = 0; i < n; i++)
    {
        for (int j = i; j < ans[i].size(); j++)
        {
            swap(ans[i][j], ans[j][i]);
        }
    }
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n / 2; j++)
        {
            swap(ans[i][j], ans[i][n - j - 1]);
        }
    }
}
int main()
{
    int m,n;
    cout<<"Enter size of matrix(m n):";
    cin>>m>>n;
    cout<<"Enter "<<m*n<<" elements:";
    vector<vector<int>> arr;
    for(int i=0;i<m;i++)
    {
        vector<int> r;
        for(int j=0;j<n;j++)
        {
            int a;
            cin>>a;
            r.push_back(a);
        }
        arr.push_back(r);
    }
    cout << "Matrix Before Rotation:\n";
    for (int i = 0; i < arr.size(); i++)
    {
        cout << "[";
        for (int j = 0; j < arr[0].size(); j++)
        {
            cout << arr[i][j] << " ";
        }
        cout << "]\n";
    }
    rotate(arr);
    cout << "Matrix After Rotation:\n";
    for (int i = 0; i < arr.size(); i++)
    {
        cout << "[";
        for (int j = 0; j < arr[0].size(); j++)
        {
            cout << arr[i][j] << " ";
        }
        cout << "]\n";
    }
}
/*
Sample Input: 
Enter size of matrix(m n):3 3
Enter 9 elements:1 2 3 4 5 6 7 8 9

Sample Output:
Matrix Before Rotation:
[1 2 3 ]
[4 5 6 ]
[7 8 9 ]
Matrix After Rotation:
[7 4 1 ]
[8 5 2 ]
[9 6 3 ]

Time-Complexity: O(m+n)
Space-Complexity: O(1)

*/