题解 | #二叉树中和为某一值的路径(一)#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 * };
 */

class Solution {
public:
    /**
     * 
     * @param root TreeNode类 
     * @param sum int整型 
     * @return bool布尔型
     */
    bool flag=false;
    bool hasPathSum(TreeNode* root, int sum) {
        Find(root,sum);
        return flag;
        // write code here
    }

    void Find(TreeNode *root,int sum){
        //递归出口
        if(root==NULL){
            return;
        }
        //dfs路径已走完
        else if(!root->left&&!root->right&&root->val==sum){
            flag=true;
        }
        //继续走dfs路径
        else{
            if(root->left){
                Find(root->left,sum-root->val);
            }
            if(root->right){
                Find(root->right,sum-root->val);
            }
        }
    }
};