LeetCode 之 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.,  +  +  +  = 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.

给定一个三角形，求最小路径。每层只能选一个整数，上一层和下一层的数必须是相邻的。

class Solution {
public:
    int minimumTotal(vector<vector<int>>& triangle) {
        for (int i = triangle.size() - 2; i >= 0; --i)
        {
            for (int j = 0; j < triangle[i].size(); ++j)
            {
                triangle[i][j] += min(triangle[i + 1][j], triangle[i + 1][j + 1]);
            }
        }
        return triangle[0][0];
    }
};