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:
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
SOLUTION:
import bisect
class Solution:
def diagonalSort(self, mat: List[List[int]]) -> List[List[int]]:
m = len(mat)
n = len(mat[0])
diags = {}
for i in range(m):
for j in range(n):
if i - j in diags:
bisect.insort(diags[i - j], mat[i][j])
else:
diags[i - j] = [mat[i][j]]
for i in range(m):
for j in range(n):
mat[i][j] = diags[i - j][min(i, j)]
return mat
# import bisect
# class Solution:
# def diagonalSort(self, mat: List[List[int]]) -> List[List[int]]:
# m = len(mat)
# n = len(mat[0])
# vals = [[] for i in range(m + n - 1)]
# curr = 0
# for i in range(m):
# x, y = i, 0
# while x < m and y < n:
# bisect.insort(vals[curr], mat[x][y])
# x += 1
# y += 1
# curr += 1
# for i in range(1, n):
# x, y = 0, i
# while x < m and y < n:
# bisect.insort(vals[curr], mat[x][y])
# x += 1
# y += 1
# curr += 1
# curr = 0
# for i in range(m):
# x, y = i, 0
# while x < m and y < n:
# mat[x][y] = vals[curr][y]
# x += 1
# y += 1
# curr += 1
# for i in range(1, n):
# x, y = 0, i
# while x < m and y < n:
# mat[x][y] = vals[curr][x]
# x += 1
# y += 1
# curr += 1
# return mat
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