triangle medium

Author: weiy

Array/Triangle.py

@@ -0,0 +1,46 @@
+"""
+Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below.
+
+For example, given the following triangle
+
+[
+     [2],
+    [3,4],
+   [6,5,7],
+  [4,1,8,3]
+]
+The minimum path sum from top to bottom is 11 (i.e., 2 + 3 + 5 + 1 = 11).
+
+Note:
+
+Bonus point if you are able to do this using only O(n) extra space, where n is the total number of rows in the triangle.
+
+从底到顶，min(self+right)。
+
+O(1) 空间。
+
+beat
+99%
+
+测试地址：
+https://leetcode.com/problems/triangle/description/
+
+
+
+"""
+class Solution(object):
+    def minimumTotal(self, triangle):
+        """
+        :type triangle: List[List[int]]
+        :rtype: int
+        """
+        
+        for i in range(len(triangle)-2, -1, -1):
+            length = len(triangle[i])
+            for j in range(length):
+
+                _right = triangle[i+1][j+1] 
+                _self = triangle[i+1][j]
+                mins = min(_right, _self)
+                triangle[i][j] += mins
+        return min(triangle[0])