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).
由于每次在下面一行選擇時只能選和上面選中的相鄰的，所以從上往下遍歷，每一行每一個元素都取上一行與自己相鄰的元素中最小的與自己相加，存在自己這里。遍歷完后再遍歷最后一行，找到最小的元素，就是我們要的最小和。

var minimumTotal = function(triangle) {
    var row = triangle.length;
    var rec = [triangle[0][0]];
    for (let i = 1;i < row;i++) {
        for (let j = 0;j < triangle[i].length;j++) {
            if (j===0)
                triangle[i][j] = triangle[i-1][j] + triangle[i][j];
            else if (j===triangle[i].length-1)
                triangle[i][j] = triangle[i-1][j-1] + triangle[i][j];
            else {
                if(triangle[i-1][j-1]>triangle[i-1][j])
                    triangle[i][j] = triangle[i-1][j] + triangle[i][j];
                else
                    triangle[i][j] = triangle[i-1][j-1] + triangle[i][j];
            }
        }
    }
    var min = triangle[row-1][0];
    for (let i = 1;i < triangle[row-1].length;i++) {
        if (triangle[row-1][i]<min)
            min = triangle[row-1][i];
    }
    return min;
};