Leetcode 25-30

No. 25 Reverse Nodes in k-Group （HARD）

Solution:

 

No. 26 Remove Duplicates from Sorted Array （EASY，PASS）

Note: Return the length rather than the sorted array.

No. 27 Remove Element （EASY）

Solution:

Note: 题目中要求不能设置新的array。

代码：

class Solution:
    def removeElement(self, nums: List[int], val: int) -> int:
        if not nums:
            return 0
        
        start, end = 0, len(nums)-1
        
        while start <= end:
            if nums[start] == val:
                nums[start], nums[end], end = nums[end], nums[start], end-1
            else:
                start += 1
        
        return start

No. 28 Implement strStr() （EASY，PASS）

No. 29 Divide Two Integers

 Solution: 

 1 class Solution:
 2     def divide(self, dividend: int, divisor: int) -> int:
 3         if dividend == 0:
 4             return 0
 5         
 6         positive = (dividend < 0) is (divisor < 0)
 7         dividend, divisor = abs(dividend), abs(divisor)
 8         
 9         res = 0
10         
11         while dividend >= divisor:
12             temp, i = divisor, 1
13             while dividend >= temp:
14                 dividend -= temp
15                 res += i
16                 i <<= 1
17                 temp <<= 1
18         
19         if not positive:
20             res = -res
21         
22         return min(max(-2147483648, res), 2147483647)

 

No. 30 Substring with Concatenation of All Words （HARD）

posted @ 2019-06-06 14:19  ArthurH  阅读(105)  评论(0)  编辑  收藏  举报