Description#
A matrix diagonal is a diagonal line of cells starting from some cell in either the topmost row or leftmost column and going in the bottom-right direction until reaching the matrix's end. For example, the matrix diagonal starting from mat[2][0]
, where mat
is a 6 x 3
matrix, includes cells mat[2][0]
, mat[3][1]
, and mat[4][2]
.
Given an m x n
matrix mat
of integers, sort each matrix diagonal in ascending order and return the resulting matrix.
Example 1:
![](https://spcdn.pages.dev/leetcode/problems/1329.Sort%20the%20Matrix%20Diagonally/images/1482_example_1_2.png)
Input: mat = [[3,3,1,1],[2,2,1,2],[1,1,1,2]]
Output: [[1,1,1,1],[1,2,2,2],[1,2,3,3]]
Example 2:
Input: mat = [[11,25,66,1,69,7],[23,55,17,45,15,52],[75,31,36,44,58,8],[22,27,33,25,68,4],[84,28,14,11,5,50]]
Output: [[5,17,4,1,52,7],[11,11,25,45,8,69],[14,23,25,44,58,15],[22,27,31,36,50,66],[84,28,75,33,55,68]]
Constraints:
m == mat.length
n == mat[i].length
1 <= m, n <= 100
1 <= mat[i][j] <= 100
Solutions#
Solution 1#
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| class Solution:
def diagonalSort(self, mat: List[List[int]]) -> List[List[int]]:
m, n = len(mat), len(mat[0])
for k in range(min(m, n) - 1):
for i in range(m - 1):
for j in range(n - 1):
if mat[i][j] > mat[i + 1][j + 1]:
mat[i][j], mat[i + 1][j + 1] = mat[i + 1][j + 1], mat[i][j]
return mat
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| class Solution {
public int[][] diagonalSort(int[][] mat) {
int m = mat.length, n = mat[0].length;
for (int k = 0; k < Math.min(m, n) - 1; ++k) {
for (int i = 0; i < m - 1; ++i) {
for (int j = 0; j < n - 1; ++j) {
if (mat[i][j] > mat[i + 1][j + 1]) {
int t = mat[i][j];
mat[i][j] = mat[i + 1][j + 1];
mat[i + 1][j + 1] = t;
}
}
}
}
return mat;
}
}
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| class Solution {
public:
vector<vector<int>> diagonalSort(vector<vector<int>>& mat) {
int m = mat.size(), n = mat[0].size();
for (int k = 0; k < min(m, n) - 1; ++k)
for (int i = 0; i < m - 1; ++i)
for (int j = 0; j < n - 1; ++j)
if (mat[i][j] > mat[i + 1][j + 1])
swap(mat[i][j], mat[i + 1][j + 1]);
return mat;
}
};
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| func diagonalSort(mat [][]int) [][]int {
m, n := len(mat), len(mat[0])
for k := 0; k < m-1 && k < n-1; k++ {
for i := 0; i < m-1; i++ {
for j := 0; j < n-1; j++ {
if mat[i][j] > mat[i+1][j+1] {
mat[i][j], mat[i+1][j+1] = mat[i+1][j+1], mat[i][j]
}
}
}
}
return mat
}
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