[993] Cousins in Binary Tree

感覺沒什麼秘技？！就是要多加一個parent 的紀錄

看是要跑兩次function check 還是要用一個global 紀錄parent ?!

或是用structure宣告一個typedef 是存parent and depth

總而言之呢~~~~

一開始求高度很快就寫好了～要加parent check 卡了一下. 以上

/**

* Definition for a binary tree node.

* struct TreeNode {

* int val;

* struct TreeNode *left;

* struct TreeNode *right;

* };

*/

int countDep(struct TreeNode* node, int val, int depth){

if (node == NULL)

return 0;

if (node->val == val)

return depth;

depth +=1;

return (countDep(node->left, val,depth) + countDep(node->right, val,depth));

}

bool checkParent(struct TreeNode* root, int x, int y)

{

if (root==NULL)

return false;

if (root->left == NULL)

return checkParent(root->right , x,y);

if (root->right == NULL)

return checkParent(root->left , x,y);

if (((root->left->val == x) && (root->right->val == y)) ||

((root->left->val == y) && (root->right->val == x)) )

return true;

return (checkParent(root->left , x, y) || checkParent(root->right , x,y));

}

bool isCousins(struct TreeNode* root, int x, int y){

int xHeight = countDep(root, x, 0);

int yHeight = countDep(root, y, 0);

if (xHeight == yHeight)

return !checkParent(root, x, y);

return false;

}