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fix build_tree, binary_search_tree.cs

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fix two figures
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krahets
2023-09-15 02:08:09 +08:00
parent af2aeb0897
commit cb9c14f5ff
13 changed files with 69 additions and 72 deletions
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14
codes/cpp/chapter_divide_and_conquer/build_tree.cpp
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@ -7,18 +7,18 @@
#include "../utils/common.hpp"
/* 构建二叉树：分治 */
TreeNode *dfs(vector<int> &preorder, vector<int> &inorder, unordered_map<int, int> &hmap, int i, int l, int r) {
TreeNode *dfs(vector<int> &preorder, unordered_map<int, int> &inorderMap, int i, int l, int r) {
// 子树区间为空时终止
if (r - l < 0)
return NULL;
// 初始化根节点
TreeNode *root = new TreeNode(preorder[i]);
// 查询 m ，从而划分左右子树
int m = hmap[preorder[i]];
int m = inorderMap[preorder[i]];
// 子问题：构建左子树
root->left = dfs(preorder, inorder, hmap, i + 1, l, m - 1);
root->left = dfs(preorder, inorderMap, i + 1, l, m - 1);
// 子问题：构建右子树
root->right = dfs(preorder, inorder, hmap, i + 1 + m - l, m + 1, r);
root->right = dfs(preorder, inorderMap, i + 1 + m - l, m + 1, r);
// 返回根节点
return root;
}
@ -26,11 +26,11 @@ TreeNode *dfs(vector<int> &preorder, vector<int> &inorder, unordered_map<int, in
/* 构建二叉树 */
TreeNode *buildTree(vector<int> &preorder, vector<int> &inorder) {
// 初始化哈希表，存储 inorder 元素到索引的映射
unordered_map<int, int> hmap;
unordered_map<int, int> inorderMap;
for (int i = 0; i < inorder.size(); i++) {
hmap[inorder[i]] = i;
inorderMap[inorder[i]] = i;
}
TreeNode *root = dfs(preorder, inorder, hmap, 0, 0, inorder.size() - 1);
TreeNode *root = dfs(preorder, inorderMap, 0, 0, inorder.size() - 1);
return root;
}