leetcode No112. Path Sum

Question:


Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.
For example:
Given the below binary tree and  sum = 22
,
              5
             / \
            4   8
           /   / \
          11  13  4
         /  \      \
        7    2      1

return true, as there exist a root-to-leaf path  5->4->11->2  which sum is 22.
경로가 있는지 없는지sum

Algorithm:


DFS

Accepted Code:

/**
 * 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:
    bool hasPathSum(TreeNode* root, int sum) {
        if(root==NULL)
            return false;
        else if(root->val==sum&&root->left==NULL&&root->right==NULL)
            return true;
        bool b1=false;
        bool b2=false;
        int curVal=root->val;
        b1=hasPathSum(root->left,sum-curVal);
        b2=hasPathSum(root->right,sum-curVal);
        return b1||b2;
    }
};

좋은 웹페이지 즐겨찾기