binaryTree sum notlimitted head and tai

binaryTree sum notlimitted head and tail

感想

详细代码
感想
应用了全局变量
所有函数的返回值现在没有用上。

代码之双递归

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

 
/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param root TreeNode类 
 * @param sum int整型 
 * @return int整型
 */
typedef struct TreeNode pTreeNode;
int gSum=0;
int gRet=0;

void dfs(pTreeNode * pTreeNode, int currSum){

    //exit
    if(NULL == pTreeNode){
        return ;
    }
    //exit 2
    if(pTreeNode->val == currSum){
        gRet++;
    }
    //deep
    dfs(pTreeNode->left , currSum - pTreeNode->val);

        dfs(pTreeNode->right , currSum - pTreeNode->val);

}


int FindPath(struct TreeNode* root, int sum ) {
    // write code here
    
    if(NULL == root ){
        return 0;
    }
    gSum = sum;
    //base level get result
    int result = 0; 
    
    //gRet 
    dfs(root,gSum);//from selft

    //left 
    FindPath(root->left,gSum);
    //right
    FindPath(root->right,gSum);
    //return final result

    return gRet;
} 

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