Update to 016

Update to 016

Author: nature1995

.idea/Leetcode-Python3.iml

@@ -1,7 +1,27 @@
 #!usr/bin/env python3
 # -*- coding:utf-8 -*-
+'''
+Write a function to find the longest common prefix string amongst an array of strings.
+'''
 
 
+class Solution(object):
+    def longestCommonPrefix(self, strs):
+        """
+        :type strs: List[str]
+        :rtype: str
+        """
+        if not strs:
+            return ""
+        longest = strs[0]
+        for i in range(len(strs[0])):
+            for str in strs:
+                if len(str) <= i or strs[0][i] != str[i]:
+                    return strs[0][:i]
+        return strs[0]
 
 
+if __name__ == "__main__":
+    assert Solution().longestCommonPrefix(["", "heabc", "hell"]) == ""
+
 

.idea/misc.xml

@@ -1,7 +1,51 @@
 #!usr/bin/env python3
 # -*- coding:utf-8 -*-
+'''
+Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.
 
+Note:
+Elements in a triplet (a,b,c) must be in non-descending order. (ie, a ≤ b ≤ c)
+The solution set must not contain duplicate triplets.
+    For example, given array S = {-1 0 1 2 -1 -4},
 
+    A solution set is:
+    (-1, 0, 1)
+    (-1, -1, 2)
+'''
 
 
+class Solution:
+    def threeSum(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: List[List[int]]
+        """
+        result = []
+        nums.sort()
+
+        for i in range(len(nums) - 2):
+            if i == 0 or nums[i] > nums[i - 1]:
+                left = i + 1
+                right = len(nums) - 1
+                while left < right:
+                    # 注意这里不要用sum()
+                    li = nums[i] + nums[left] + nums[right]
+                    if li == 0:
+                        result.append([nums[i], nums[left], nums[right]])
+                        left += 1
+                        right -= 1
+                        while left < right and nums[left] == nums[left - 1]:
+                            left += 1
+                        while left < right and nums[right] == nums[right + 1]:
+                            right -= 1
+                    elif li > 0:
+                        right -= 1
+                    else:
+                        left += 1
+        return result
+
+
+if __name__ == "__main__":
+    assert Solution().threeSum([-1,0,1,0]) == [[-1,0,1]]
+
 

.idea/modules.xml

@@ -1,7 +1,41 @@
 #!usr/bin/env python3
 # -*- coding:utf-8 -*-
+'''
+Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution.
 
+    For example, given array S = {-1 2 1 -4}, and target = 1.
 
+    The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).
+'''
 
 
+class Solution(object):
+    def threeSumClosest(self, nums, target):
+        """
+        :type nums: List[int]
+        :type target: int
+        :rtype: int
+        """
+        nums.sort()
+        result = 0
+        # Init the distance between result and target with a very large number
+        distance = pow(2, 32) - 1
+        for i in range(len(nums) - 2):
+            left = i + 1
+            right = len(nums) - 1
+            while left < right:
+                li = nums[i] + nums[left] + nums[right]
+                if li == target:
+                    return target
+                if abs(li - target) < distance:
+                    result = li
+                    distance = abs(li - target)
+                elif li > target:
+                    right -= 1
+                else:
+                    left += 1
+        return result
 
+
+if __name__ == "__main__":
+    assert Solution().threeSumClosest([1, 1, 1, 1], -100) == 3