做美团类似的网站爱链在线

晴问 通过中序遍历判断左右子树，接着从层序遍历中，把左子树的层序遍历和右子树的层序遍历提取出来

#include <bits/stdc++.h>using namespace std;vector<int> in, cc;struct treeNode {int data;treeNode *left;treeNode *right;treeNode(int data) : data(data), left(nullptr), right(nullptr) {}
};treeNode *dfs(treeNode *&root, vector<int> &level, int in_left, int in_right) {if (level.size() == 0) return nullptr;int curRootNum = level[0], rootInIndex;for (rootInIndex = in_left; rootInIndex <= in_right; ++rootInIndex) {if (in[rootInIndex] == curRootNum) break;}root = new treeNode(curRootNum);set<int> leftTree;for (int i = in_left; i < rootInIndex; ++i) {leftTree.insert(in[i]);}vector<int> level_left, level_right;for (int i = 0; i < level.size(); ++i) {if (level[i] == curRootNum) continue;if (leftTree.find(level[i]) != leftTree.end()) {level_left.push_back(level[i]);} else {level_right.push_back(level[i]);}}dfs(root->left, level_left, in_left, rootInIndex - 1);dfs(root->right, level_right, rootInIndex + 1, in_right);return root;
}vector<int> result;void preOrder(treeNode *root) {if (root == nullptr) return;result.push_back(root->data);preOrder(root->left);preOrder(root->right);
}int main() {int n;cin >> n;for (int i = 0; i < n; ++i) {int num;cin >> num;cc.push_back(num);}for (int i = 0; i < n; ++i) {int num;cin >> num;in.push_back(num);}treeNode *root;dfs(root, cc, 0, n - 1);preOrder(root);for (int i = 0; i < result.size(); ++i) {cout << result[i];if (i != result.size() - 1) cout << " ";}return 0;
}