120. Triangle

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.难度：medium题目：给定一三角形数组，找出从上到下最小的路径和。每步只可以向下一行的相邻元素移动。Runtime: 4 ms, faster than 87.60% of Java online submissions for Triangle.Memory Usage: 38.5 MB, less than 100.00% of Java online submissions for Triangle.class Solution { public int minimumTotal(List<List<Integer>> triangle) { int m = triangle.size(); if (1 == m) { return triangle.get(0).get(0); } int[][] table = new int[m][m]; for (int i = 0; i < m; i++) { for (int j = 0; j <= i; j++) { table[i][j] = triangle.get(i).get(j); } } int result = table[0][0]; for (int i = 1; i < m; i++) { result = table[i][0] + table[i - 1][0]; for (int j = 0; j <= i; j++) { if (0 == j) { table[i][j] += table[i - 1][j]; } else if (j == i) { table[i][j] += table[i - 1][j - 1]; } else { table[i][j] += Math.min(table[i - 1][j], table[i - 1][j - 1]); } result = Math.min(table[i][j], result); } } return result; }}