"Leetcode 111" Minimum Depth of Binary Tree

Method 1: recursive.

intMindepth (treenode*root) {    if(Root = =NULL)return 0; if(Root->left = =NULL) {        returnMindepth (root->right) +1; } Else if(Root->right = =NULL) {        returnMindepth (Root->left) +1; } Else {        intLeft_mindepth = Mindepth (root->Left ); intRight_mindepth = Mindepth (root->Right ); returnLeft_mindepth < right_mindepth? Left_mindepth +1: Right_mindepth +1; }}

Method 2: BFS.

intMindepth (TreeNode *root) {    if(Root = =NULL)return 0; Queue<TreeNode*>Node_queue;    Node_queue.push (root); intCount =0;  while(!Node_queue.empty ()) {        intLen =node_queue.size (); Count++;  for(inti =0; i < Len; ++i) {TreeNode*nodetmp =Node_queue.front ();            Node_queue.pop (); if(nodetmp->Left ) Node_queue.push (nodetmp-Left ); if(nodetmp->Right ) Node_queue.push (nodetmp-Right ); if(Nodetmp->left = = NULL && Nodetmp->right = =NULL)returncount; }    }}

Topic Category: Two cross-tree traversal.

"Leetcode 111" Minimum Depth of Binary Tree