Classic 150 Interview Questions P48 Rotate Image

---

Timeline

Timeline

2025-11-17

init

Matrix

---

Problem:

P48 Rotate Image

https://leetcode.cn/problems/rotate-image/description/?envType=study-plan-v2&envId=top-interview-150

First flip along the diagonal, then reverse each row.

#include <vector>
#include <algorithm>
using std::vector;

class Solution {
    public:
	void rotate(vector<vector<int> > &matrix)
	{
		// First flip along the diagonal
		int i, j, n = matrix.size();
		for (i = 0; i < n; i++)
			for(j = i + 1; j< n; j++)
				std::swap(matrix[i][j], matrix[j][i]);

		// Then reverse each row
		for (i = 0; i < n; i++)
			std::reverse(matrix[i].begin(), matrix[i].end());
	}
};

leetcode hot 100 rewrite

#include <vector>
#include <algorithm>
using std::vector;

class Solution {
    public:
        void rotate(vector<vector<int> > &matrix)
        {
                int i, j, n = matrix.size();
                for (i = 0; i < n; i++) {
                        for (j = i + 1; j < n; j++) {
                                std::swap(matrix[i][j], matrix[j][i]);
                        }
                }
                for (i = 0; i < n; i++)
                        std::reverse(matrix[i].begin(), matrix[i].end());
        }
};