LeetCode OJ 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

Return6.

int max(int a, int b) {if (a > b) return a;return b;}int ans;int maxDownSum(struct TreeNode * now) {if (!now) return 0;int l = max(0, maxDownSum(now->left));int r = max(0, maxDownSum(now->right));ans = max(ans, l + r + now->val);return max(l, r) + now->val;}int maxPathSum(struct TreeNode * root) {ans = INT_MIN;maxDownSum(root);return ans;}

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