Day 7 >> Spiral Matrix II

Author: keshavsingh3197

LeetCode/December 2020/Spiral Matrix II.py

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+#https://leetcode.com/explore/challenge/card/december-leetcoding-challenge/569/week-1-december-1st-december-7th/3557/
+class Solution:
+ def generateMatrix(self, n: int) -> List[List[int]]:
+ l=[[i for i in range(1,n+1)] for i in range(n)]
+ k=n
+ for i in range(n//2):
+ if n>1:
+ # diagonal 4*(k-1)
+ if i==0:
+ l[i+1][i]=4*(k-1)
+ else:
+ l[i+1][i]=l[i][i-1]+4*(k-1)
+ # top left-right
+ for j in range(i,n-i):
+ l[i][j]=l[i][j-1]+1
+ # left top-bottom
+ for j in range(i+1,n-i+1):
+ l[j][i-1]=l[j-1][i-1]-1
+ #bottom left-right
+ for j in range(i,n-i):
+ l[n-i][j]=l[n-i][j-1]-1
+ # right top-bottom
+ for j in range(i,n-i+1):
+ l[j][n-i]=l[j-1][n-i]+1
+ 
+ k-=2
+ if n>1:
+ if n%2:
+ l[n//2][n//2]=l[n//2][n//2-1]+1
+ l[n//2][n//2+1]=l[n//2-1][n//2+1]+1
+ l[n//2+1][n//2-1]=l[n//2][n//2-1]-1
+ l[n//2+1][n//2]=l[n//2+1][n//2-1]-1
+ l[n//2+1][n//2+1]=l[n//2+1][n//2]-1
+ else:
+ l[n//2][n//2]=l[n//2][n//2-1]-1
+ return l