No.123 - LeetCode543 - 树的直径

ShellDawn

于 2019-09-25 15:30:11 发布

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分类专栏： leetcode 文章标签： LeetCode

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/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int ans;
    int dfs(TreeNode* now){
        int L = 0;
        if(now->left != NULL) L = dfs(now->left);
        int R = 0;
        if(now->right != NULL) R = dfs(now->right);
        ans = max(ans,L+R+1);
        return max(L,R)+1;
    }
    int diameterOfBinaryTree(TreeNode* root) {
        ans = 1;
        if(root != NULL) dfs(root);
        return ans;
    }
};