Triangle

Description

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.

Solution(javascript)

/**
 * @param {number[][]} triangle
 * @return {number}
 */
var minimumTotal = function(triangle) {
    for(let d = triangle.length-2; d >=0; d--){
        const row = triangle[d];
        for(let i = 0; i < row.length; i++){
            row[i] += Math.min(triangle[d+1][i], triangle[d+1][i+1]);
        }
    }
    return triangle[0][0];
};