劍指Offer_編程題_4
阿新 • • 發佈：2018-04-22
題目 tor 結果 else 編程 sub node UC urn
題目描述
輸入某二叉樹的前序遍歷和中序遍歷的結果，請重建出該二叉樹。假設輸入的前序遍歷和中序遍歷的結果中都不含重復的數字。例如輸入前序遍歷序列{1,2,4,7,3,5,6,8}和中序遍歷序列{4,7,2,1,5,3,8,6}，則重建二叉樹並返回。/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
TreeNode* reConstructBinaryTree(vector<int> pre,vector<int> vin) {
int vinSize = vin.size();
if(vinSize == 0) return NULL;
vector<int>pre_left,pre_right,vin_left,vin_right;
int val = pre[0];
int i;
for(i = 0; i < vinSize; i ++) {
if(vin[i] == val){
break;
}
}
int index = i;
TreeNode* tree = new TreeNode(val);
for(i = 0; i < vinSize; i++ ) {
if(i < index) {
vin_left.push_back(vin[i]);
pre_left.push_back(pre[i+1]);
} else if(i > index) {
vin_right.push_back(vin[i]);
pre_right.push_back(pre[i]);
}
}
tree->left = reConstructBinaryTree(pre_left,vin_left);
tree->right = reConstructBinaryTree(pre_right,vin_right);
return tree;
}
};
劍指Offer_編程題_4