Self-Learned Algorithms - 07

This is my learning note about algorithms.

Reference

《小浩算法》) - 排序系列

905.按奇偶排序数组

https://leetcode-cn.com/problems/sort-array-by-parity/

题解

奇偶数的话维护双指针就可以了

解法

按照模2的结果排序

1 2	A.sort(key = lambda x: x % 2) return A

奇数数组和偶数数组拼接

ans1 = []
ans2 = []
for i in A:
  if i % 2 == 0:
  	ans1.append(i)
  else:
  	ans2.append(i)
return ans1 + ans2

双指针同向遍历

i = 0
for j in range(len(A)):
  if A[j] % 2 == 0:
    A[i], A[j] = A[j], A[i]
    i += 1
return A

双指针双向遍历

i, j = 0, len(A)-1
while i < j:
  while A[i] % 2 == 0 and i < j:
  	i += 1
  while A[j] % 2 == 1 and i < j:
  	j -= 1
  A[i], A[j] = A[j], A[i]
return A