Insertion Sort/ Find Minimum in Rotated Sorted Array

Author: gavinfish

147 Insertion Sort List.py

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+'''
+Sort a linked list using insertion sort.
+'''
+
+# Definition for singly-linked list.
+class ListNode(object):
+    def __init__(self, x):
+        self.val = x
+        self.next = None
+
+
+class Solution(object):
+    def insertionSortList(self, head):
+        """
+        :type head: ListNode
+        :rtype: ListNode
+        """
+        dummy = ListNode(-1)
+        cur = dummy
+        while head:
+            # check if it is needed to reset the cur pointer
+            if cur and cur.val > head.val:
+                cur = dummy
+            # find the place to insert
+            while cur.next and cur.next.val < head.val:
+                cur = cur.next
+            # insert and sort the next element
+            cur.next, cur.next.next, head = head, cur.next, head.next
+        return dummy.next
+
+
+if __name__ == "__main__":
+    None

153 Find Minimum in Rotated Sorted Array.py

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+'''
+Suppose a sorted array is rotated at some pivot unknown to you beforehand.
+
+(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).
+
+Find the minimum element.
+
+You may assume no duplicate exists in the array.
+'''
+
+class Solution(object):
+    def findMin(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        left, right = 0, len(nums) - 1
+        mid = 0
+        while left < right:
+            mid = (left + right) // 2
+            if nums[mid] > nums[mid + 1]:
+                return nums[mid + 1]
+            elif nums[mid] > nums[right]:
+                left = mid + 1
+            else:
+                right = mid
+        return nums[mid]
+
+
+if __name__ == "__main__":
+    assert Solution().findMin([1, 2, 3, 4, 5]) == 1
+    assert Solution().findMin([2, 3, 4, 5, 1]) == 1
+    assert Solution().findMin([5, 1, 2, 3, 4]) == 1