[Leetcode] Second Minimum Node in a Binary Tree

[Leetcode] Second Minimum Node in a Binary Tree topic

https://leetcode.com/problems/second-minimum-node-in-a-binary-tree/

Given a non-empty Special binary tree consisting of nodes with the non-negative value, where each node in this tree have ex actly or Zero sub-node. If the node has both sub-nodes, then this node's value is the smaller value among its-sub-nodes.

Given Such a binary tree, you need to output the second minimum value in the set made of all the nodes ' value in the whole Tree.

If no such second minimum value exists, output-1 instead.

Example 1:

Input:
    2
   /\
  2   5
     /\
    5   7

output:5
explanation:the Smallest value is 2, the second Smallest value is 5.

Example 2:

Input:
    2
   /\
  2   2

Output:-1
explanation:the Smallest value is 2, but there isn ' t second small EST value.

Code

34/34 test cases passed.
Runtime:0 ms

/** * Definition for a binary tree node.
 * struct TreeNode {* int val;
 * struct TreeNode *left;
 * struct TreeNode *right;
 * }; */#define INF 0x7fffffff//The minimum value (different from the minimum value of root->val) int traverse (struct treenode* node, struct Treenod) when node nodes are found as subtree
    e* root) {int lval = INF;
    if (node->left! = NULL) {lval = Traverse (node->left, Root);
    } int rval = INF;
    if (node->right! = NULL) {rval = Traverse (node->right, Root);
    } int val = INF;
    if (node->val! = root->val) {val = node->val;
        } if (lval! = root->val) {if (val > lval) {val = lval;
        }} if (Rval! = root->val) {if (val > Rval) {val = rval;
}} return Val;
    } int Findsecondminimumvalue (struct treenode* root) {if (root = = NULL) {return-1;
} if (root->left = = NULL && Root->right = = null) {return-1;    } int val = INF;  val = Traverse (root, root);//val = inf because there is no value different from Root->val if (val = = Root->val | | val = = INF) {return
    -1;
    } else {return val; }
}