2023-12-10 Daily Challenge

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In: DailyChallenge
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Today I have done leetcode's December LeetCoding Challenge with cpp.

December LeetCoding Challenge 10

Description

Transpose Matrix

Given a 2D integer array matrix, return the transpose of matrix.

The transpose of a matrix is the matrix flipped over its main diagonal, switching the matrix's row and column indices.

 

Example 1:

Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
Output: [[1,4,7],[2,5,8],[3,6,9]]

Example 2:

Input: matrix = [[1,2,3],[4,5,6]]
Output: [[1,4],[2,5],[3,6]]

 

Constraints:

  • m == matrix.length
  • n == matrix[i].length
  • 1 <= m, n <= 1000
  • 1 <= m * n <= 105
  • -109 <= matrix[i][j] <= 109

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  vector<vector<int>> transpose(vector<vector<int>>& matrix) {
    int rows = matrix.size();
    int cols = matrix.front().size();
    vector<vector<int>> answer;
    for(int i = 0; i < cols; ++i) {
      vector<int> row(rows);
      for(int j = 0; j < rows; ++j) {
        row[j] = matrix[j][i];
      }
      answer.emplace_back(row);
    }
    return move(answer);
  }
};

// Accepted
// 36/36 cases passed (7 ms)
// Your runtime beats 97.84 % of cpp submissions
// Your memory usage beats 13.79 % of cpp submissions (10.8 MB)
Algorithm