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).

 

public class Solution {
    public int minimumTotal(List<List<Integer>> triangle) {
        if (triangle.size() == 1) {
        	return triangle.get(0).get(0);
        }
        int[] dp = new int[triangle.size()];
        for (int i = 0; i < triangle.get(triangle.size()-1).size(); i++) {
			dp[i] = triangle.get(triangle.size()-1).get(i);
		}
        for (int i = triangle.size()-2; i >= 0; i--) {
			for (int j = 0; j < triangle.get(i).size(); j++) {
				dp[j] = Math.min(dp[j], dp[j+1]) + triangle.get(i).get(j);
			}
		}
        return dp[0];
    }
}