Rotate Image Solutions in C++

// Source : https://oj.leetcode.com/problems/rotate-image/
// Author : Hao Chen
// Date   : 2014-06-27



#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <vector>
using namespace std;

void rotate(vector<vector<int> > &matrix) {

    int n = matrix.size();

    for( int i=0; i<n/2; i++ ){
        int low=i, high=n-i-1;
        for (int j=low; j<high; j++){
            int tmp;
            tmp = matrix[i][j];
            // left to top 
            matrix[i][j] = matrix[n-j-1][i];
            // bottom to left
            matrix[n-j-1][i] = matrix[n-i-1][n-j-1];
            // right to bottom
            matrix[n-i-1][n-j-1] = matrix[j][n-i-1];
            // top to right
            matrix[j][n-i-1] = tmp;
        }
    }
}

void printMatrix(vector<vector<int> > &matrix) 
{
    for(int i=0; i<matrix.size(); i++){
        for(int j=0; j< matrix[i].size(); j++) {
            printf("%3d ", matrix[i][j]) ;
        }
        cout << endl;
    }
    cout << endl;
}


int main(int argc, char** argv)
{
    int n = 2;
    if (argc>1){
        n = atoi(argv[1]);
    }
    vector< vector<int> > matrix;
    for (int i=1; i<=n; i++) {
        vector<int> v;
        for(int j=1; j<=n; j++){
            v.push_back( (i-1)*n + j );
        }
        matrix.push_back(v);
    }

    printMatrix(matrix);
    rotate(matrix);
    printMatrix(matrix);

    return 0;
}

#include <algorithm>    // std::reverse
#include <vector>

using std::vector; using std::reverse; using std::swap;

class Solution {
public:
    void rotate(vector<vector<int> > &matrix) {
        reverse(matrix.begin(), matrix.end());
        for (decltype(matrix.size()) i=0; i<matrix.size(); ++i)
            for (decltype(matrix.size()) j=i; j<matrix[i].size(); ++j)
                swap(matrix[i][j], matrix[j][i]);
    }
};

/// Source : https://leetcode.com/problems/rotate-image/description/
/// Author : liuyubobobo
/// Time   : 2018-09-13

#include <iostream>
#include <vector>

using namespace std;


/// Ad-Hoc
/// Time Complexity: O(n^2)
/// Space Complexity: O(1)
class Solution {
public:
    void rotate(vector<vector<int>>& matrix) {

        int n = matrix.size();
        for(int i = 0; i <= n / 2; i ++)
            for(int j = i; j < n - 1 - i; j ++){
                int t = matrix[i][j];
                matrix[i][j] = matrix[n - 1 - j][i];
                matrix[n - 1 - j][i] = matrix[n - 1 - i][n - 1 - j];
                matrix[n - 1 - i][n - 1 - j] = matrix[j][n - 1 - i];
                matrix[j][n - 1 - i] = t;
                Solution::print_matrix(matrix);
            }
    }

    static void print_matrix(const vector<vector<int>>& m){
        for(int i = 0; i < m.size(); i ++){
            for(int j = 0; j < m[i].size(); j ++)
                cout << m[i][j] << " ";
            cout << endl;
        }
        cout << endl;
    }
};


int main() {

    vector<vector<int>> matrix1 = {
            {1, 2, 3},
            {4, 5, 6},
            {7, 8, 9}
    };
    Solution().rotate(matrix1);
    Solution::print_matrix(matrix1);

    vector<vector<int>> matrix2 = {
            {1, 2, 3, 4},
            {5, 6, 7, 8},
            {9, 10, 11, 12},
            {13, 14, 15, 16}
    };
    Solution().rotate(matrix2);
    Solution::print_matrix(matrix2);

    return 0;
}

/// Source : https://leetcode.com/problems/rotate-image/description/
/// Author : liuyubobobo
/// Time   : 2018-12-16

#include <iostream>
#include <vector>

using namespace std;


/// Reverse diagonally and then reverse row
/// Time Complexity: O(n^2)
/// Space Complexity: O(1)
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 < n - i; j ++)
                swap(matrix[i][j], matrix[n - j - 1][n - i - 1]);

        for(int i = 0; i < n / 2; i ++)
            for(int j = 0; j < n; j ++)
                swap(matrix[i][j], matrix[n - i - 1][j]);
    }
};


void print_matrix(const vector<vector<int>>& m){
    for(int i = 0; i < m.size(); i ++){
        for(int j = 0; j < m[i].size(); j ++)
            cout << m[i][j] << " ";
        cout << endl;
    }
    cout << endl;
}

int main() {

    vector<vector<int>> matrix1 = {
            {1, 2, 3},
            {4, 5, 6},
            {7, 8, 9}
    };
    Solution().rotate(matrix1);
    print_matrix(matrix1);

    vector<vector<int>> matrix2 = {
            {1, 2, 3, 4},
            {5, 6, 7, 8},
            {9, 10, 11, 12},
            {13, 14, 15, 16}
    };
    Solution().rotate(matrix2);
    print_matrix(matrix2);

    return 0;
}