leetcode刷题，总结，记录，备忘111

leetcode111Minimum Depth of Binary Tree

Given a binary tree, find its minimum depth.

The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

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通过队列保存树的每个节点，使用一个变量记录当前层的节点个数，每遍历完一层深度加1，当遇到叶节点的时候返回深度即可，比较简单的题目。
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int minDepth(TreeNode* root) {
if (root == NULL)
{
return 0;
}

queue<TreeNode*> qt;
qt.push(root);
int deep = 1;
int count = 1;

while (!qt.empty())
{
TreeNode * t = qt.front();
qt.pop();
count--;
if (t->left == NULL && t->right == NULL)
{
return deep;
}
if (t->left)
{
qt.push(t->left);
}
if (t->right)
{
qt.push(t->right);
}

if (count == 0)
{
count = qt.size();
deep++;
}

}

return deep;
}
};