用的层序遍历
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* struct TreeNode *left;
* struct TreeNode *right;
* };
*/
int findBottomLeftValue(struct TreeNode* root) {
if(!root->left&&!root->right) return root->val;
struct TreeNode* queue[20000]={0};
int front=0,tail=0;
queue[tail++]=root;
int end=0;
int n=0;
int x;
while(front!=tail){
struct TreeNode* temp=queue[front];
n++;
if(n==1) x=temp->val;
if(front==end){
if(temp->left) queue[tail++]=temp->left;
if(temp->right) queue[tail++]=temp->right;
end=tail-1;
n=0;
}else{
if(temp->left) {
queue[tail++]=temp->left;
}
if(temp->right) {
queue[tail++]=temp->right;
}
}
front++;
}
return x;
}结果：
