MinimumTriangleSum.java

package com.interview.dynamic;

import java.util.List;

/**
 * Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on
 * the row below.
 * https://leetcode.com/problems/triangle/
 */
public class MinimumTriangleSum {
    public int minimumTotal(List<List<Integer>> triangle) {
        int n = triangle.size();
        int[] dp = new int[n];

        for (int i = 0; i < triangle.get(n - 1).size(); i++) {
            dp[i] = triangle.get(n - 1).get(i);
        }

        for (int i = triangle.size() - 2; i >= 0; i--) {
            for (int j = 0; j < triangle.get(i).size(); j++) {
                dp[j] = triangle.get(i).get(j) + Math.min(dp[j], dp[j + 1]);
            }
        }
        return dp[0];
    }
}