@@ -93,6 +93,62 @@ class Solution:
9393 return nums
9494 ```
9595
96+ ### [ 有序数组的平方] ( https://leetcode.cn/problems/squares-of-a-sorted-array/ )
97+ > 给你一个按 非递减顺序 排序的整数数组 nums,返回 每个数字的平方 组成的新数组,要求也按 非递减顺序 排序。
98+
99+ 思路:本题经典的双指针法,但有两种思路,一是从小到大去排列,一种是从大到小逆序排列,但第二种更直接,第一种需要先找到最小值在的位置,而最大值我们是知道的,不是在数组头部就是数组尾部。
100+ 101+ ** Python版本一**
102+ ``` python
103+ class Solution :
104+ def sortedSquares (self nums : List[int ]) -> List[int ]:
105+ pos = 0
106+ while pos < len (nums) and nums[pos] < 0 : pos += 1
107+ 108+ neg_nums = nums[0 :pos]
109+ neg_nums = neg_nums[::- 1 ] # reverse
110+ pos_nums = nums[pos:len (nums)]
111+ 112+ res = list ()
113+ ni, pi = 0 , 0
114+ while ni < len (neg_nums) or pi < len (pos_nums):
115+ if ni >= len (neg_nums):
116+ res.append(pos_nums[pi] * pos_nums[pi])
117+ pi += 1
118+ continue
119+ if pi >= len (pos_nums):
120+ res.append(neg_nums[ni] * neg_nums[ni])
121+ ni += 1
122+ continue
123+ if abs (neg_nums[ni]) < pos_nums[pi]:
124+ res.append(neg_nums[ni] * neg_nums[ni])
125+ ni += 1
126+ else :
127+ res.append(pos_nums[pi] * pos_nums[pi])
128+ pi += 1
129+ return res
130+ ```
131+ 132+ ** Python版本二**
133+ ``` python
134+ 135+ class Solution :
136+ def sortedSquares (self nums : List[int ]) -> List[int ]:
137+ res = [0 ] * len (nums)
138+ i, j, r = 0 , len (nums) - 1 , len (nums) - 1
139+ while i <= j:
140+ if nums[i] * nums[i] > nums[j] * nums[j]:
141+ res[r] = nums[i] * nums[i]
142+ i = i + 1
143+ else :
144+ res[r] = nums[j] * nums[j]
145+ j = j - 1
146+ r = r - 1
147+ 148+ return res
149+ 150+ ```
151+ 96152
97153### [ spiral-matrix] ( https://leetcode-cn.com/problems/spiral-matrix/ )
98154
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