Completed Leetcode 11, 15 and 75

Problem 1-Leetcode75.py

@@ -0,0 +1,20 @@
+#Time complexity: O(n)
+#Space complexity: O(1)
+
+class Solution(object):
+    def sortColors(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: None Do not return anything, modify nums in-place instead.
+        """
+        l, m, h = 0, 0, len(nums) - 1
+        while m <= h:
+            if nums[m] == 2:
+                nums[m], nums[h] = nums[h], nums[m]
+                h -= 1
+            elif nums[m] == 0:
+                nums[m], nums[l] = nums[l], nums[m]
+                l += 1
+                m += 1
+            else: m += 1
+

Problem 2-Leetcode15.py

@@ -0,0 +1,36 @@
+#Time complexity: O(n^2)
+#Space complexity: O(1)
+
+class Solution(object):
+    def threeSum(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: List[List[int]]
+        """
+        if len(nums) < 3:
+            return []
+
+        n = len(nums)
+        nums.sort()
+        result = []
+
+        for i in range(n):
+            if i != 0 and nums[i] == nums[i - 1]: continue
+            if nums[i] > 0: break
+            l, r = i + 1, n - 1
+
+            while l < r:
+                sum = nums[i] + nums[l] + nums[r]
+                if sum == 0:
+                    result.append([nums[i], nums[l], nums[r]])
+                    l += 1
+                    r -= 1
+                    while l < r and nums[l] == nums[l - 1] : l += 1
+                    while l < r and nums[r] == nums[r + 1] : r -= 1
+                elif sum > 0:
+                    r -= 1
+                else:
+                    l += 1
+
+        return result
+

Problem 3- Leetcode11.py

@@ -0,0 +1,22 @@
+#Time complexity: O(n)
+#Space complexity: O(1)
+
+class Solution(object):
+    def maxArea(self, height):
+        """
+        :type height: List[int]
+        :rtype: int
+        """
+        n = len(height)
+        l, r, m = 0, n - 1, 0
+
+        while l < r:
+            if height[l] < height[r]:
+                m = max(m, height[l] * (r - l))
+                l += 1
+            else:
+                m = max(m, height[r] * (r - l))
+                r -= 1
+
+        return m
+