Binary Tree Maximum Path Sum

Given a binary tree, find the maximum path sum.

The path may start and end at any node in the tree.

For example:

Given the below binary tree,

       1
      / \
     2   3

Return 6.

Analysis

1) Recursively solve this problem

2) Get largest left sum and right sum

2) Compare to the stored maximum

public class Solution {
    public int maxPathSum(TreeNode root) {
		int[] max=new int[1];
		max[0]=Integer.MIN_VALUE;
		dfs(root,max);
		return max[0];
	}
	private int dfs(TreeNode root,int[] max){
		if(root==null)
			return 0;
		int left=dfs(root.left,max);
		int right=dfs(root.right,max);
		int cur=Math.max(root.val, Math.max(root.val+left,root.val+right));
		max[0]=Math.max(max[0], Math.max(cur, root.val+left+right));
		return cur;
	}
}