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https://github.com/krahets/hello-algo.git
synced 2024-12-24 09:56:29 +08:00
fix preorder_traversal_iii_compact code
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krahets
parent
2217ffc447
commit
f71b2a40da
14 changed files with 17 additions and 37 deletions
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@ -35,7 +35,7 @@ void undoChoice(vector *state, TreeNode *choice) {
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vectorPopback(state);
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}
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/* 前序遍历：例题三 */
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/* 回溯算法：例题三 */
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void backtrack(vector *state, vector *choices, vector *res) {
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// 检查是否为解
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if (isSolution(state)) {
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@ -30,16 +30,16 @@ struct hashMapChaining {
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Pair *buckets; // 桶数组
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};
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typedef struct hashMapChaining HashMapChaining;
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typedef struct hashMapChaining hashMapChaining;
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// 函数声明
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void extend(HashMapChaining *hashmap);
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void extend(hashMapChaining *hashmap);
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/* 初始化桶数组 */
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HashMapChaining *newHashMapChaining() {
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hashMapChaining *newHashMapChaining() {
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// 为哈希表分配空间
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int tableSize = 4;
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HashMapChaining *hashmap = (HashMapChaining *)malloc(sizeof(HashMapChaining));
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hashMapChaining *hashmap = (hashMapChaining *)malloc(sizeof(hashMapChaining));
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// 初始化数组
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hashmap->buckets = (Pair *)malloc(sizeof(Pair) * tableSize);
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@ -54,7 +54,7 @@ HashMapChaining *newHashMapChaining() {
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}
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/* 销毁哈希表 */
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void delHashMapChaining(HashMapChaining *hashmap) {
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void delHashMapChaining(hashMapChaining *hashmap) {
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for (int i = 0; i < hashmap->capacity; i++) {
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Pair *pair = &hashmap->buckets[i];
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Node *node = pair->node;
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@ -70,17 +70,17 @@ void delHashMapChaining(HashMapChaining *hashmap) {
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}
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/* 哈希函数 */
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int hashFunc(HashMapChaining *hashmap, const int key) {
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int hashFunc(hashMapChaining *hashmap, const int key) {
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return key % hashmap->capacity;
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}
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/* 负载因子 */
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double loadFactor(HashMapChaining *hashmap) {
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double loadFactor(hashMapChaining *hashmap) {
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return (double)hashmap->size / (double)hashmap->capacity;
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}
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/* 查询操作 */
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const char *get(HashMapChaining *hashmap, const int key) {
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const char *get(hashMapChaining *hashmap, const int key) {
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int index = hashFunc(hashmap, key);
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Pair *pair = &hashmap->buckets[index];
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Node *node = pair->node;
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@ -93,7 +93,7 @@ const char *get(HashMapChaining *hashmap, const int key) {
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}
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/* 添加操作 */
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void put(HashMapChaining *hashmap, const int key, char *val) {
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void put(hashMapChaining *hashmap, const int key, char *val) {
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if (loadFactor(hashmap) > hashmap->loadThres) {
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extend(hashmap);
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}
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@ -134,7 +134,7 @@ void put(HashMapChaining *hashmap, const int key, char *val) {
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}
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/* 删除操作 */
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void removeItem(HashMapChaining *hashmap, int key) {
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void removeItem(hashMapChaining *hashmap, int key) {
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int index = hashFunc(hashmap, key);
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Pair *pair = &hashmap->buckets[index];
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Node *node = pair->node;
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@ -161,7 +161,7 @@ void removeItem(HashMapChaining *hashmap, int key) {
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}
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/* 扩容哈希表 */
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void extend(HashMapChaining *hashmap) {
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void extend(hashMapChaining *hashmap) {
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// 暂存原哈希表
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Pair *oldBuckets = hashmap->buckets;
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int oldCapacity = hashmap->capacity;
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@ -195,7 +195,7 @@ void extend(HashMapChaining *hashmap) {
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}
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/* 打印哈希表 */
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void print(HashMapChaining *hashmap) {
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void print(hashMapChaining *hashmap) {
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for (int i = 0; i < hashmap->capacity; i++) {
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printf("[");
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Pair *pair = &hashmap->buckets[i];
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@ -214,7 +214,7 @@ void print(HashMapChaining *hashmap) {
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/* Driver Code */
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int main() {
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/* 初始化哈希表 */
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HashMapChaining *map = newHashMapChaining();
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hashMapChaining *map = newHashMapChaining();
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/* 添加操作 */
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// 在哈希表中添加键值对 (key, value)
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@ -20,8 +20,6 @@ void preOrder(TreeNode *root) {
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if (root->val == 7) {
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// 记录解
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res.push_back(path);
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path.pop_back();
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return;
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}
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preOrder(root->left);
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preOrder(root->right);
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@ -21,8 +21,6 @@ public class preorder_traversal_iii_compact {
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if (root.val == 7) {
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// 记录解
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res.Add(new List<TreeNode>(path));
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path.RemoveAt(path.Count - 1);
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return;
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}
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preOrder(root.left);
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preOrder(root.right);
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@ -22,8 +22,6 @@ void preOrder(
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if (root.val == 7) {
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// 记录解
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res.add(List.from(path));
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path.removeLast();
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return;
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}
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preOrder(root.left, path, res);
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preOrder(root.right, path, res);
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@ -19,8 +19,6 @@ func preOrderIII(root *TreeNode, res *[][]*TreeNode, path *[]*TreeNode) {
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if root.Val.(int) == 7 {
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// 记录解
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*res = append(*res, *path)
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*path = (*path)[:len(*path)-1]
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return
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}
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preOrderIII(root.Left, res, path)
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preOrderIII(root.Right, res, path)
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@ -24,8 +24,6 @@ public class preorder_traversal_iii_compact {
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if (root.val == 7) {
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// 记录解
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res.add(new ArrayList<>(path));
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path.remove(path.size() - 1);
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return;
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}
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preOrder(root.left);
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preOrder(root.right);
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@ -18,8 +18,6 @@ function preOrder(root, path, res) {
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if (root.val === 7) {
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// 记录解
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res.push([...path]);
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path.pop();
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return;
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}
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preOrder(root.left, path, res);
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preOrder(root.right, path, res);
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@ -20,8 +20,6 @@ def pre_order(root: TreeNode):
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if root.val == 7:
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# 记录解
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res.append(list(path))
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path.pop()
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return
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pre_order(root.left)
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pre_order(root.right)
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# 回退
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@ -21,8 +21,6 @@ fn pre_order(res: &mut Vec<Vec<Rc<RefCell<TreeNode>>>>, path: &mut Vec<Rc<RefCel
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if node.borrow().val == 7 {
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// 记录解
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res.push(path.clone());
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path.remove(path.len() - 1);
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return;
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}
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pre_order(res, path, node.borrow().left.clone());
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pre_order(res, path, node.borrow().right.clone());
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@ -20,8 +20,6 @@ func preOrder(root: TreeNode?) {
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if root.val == 7 {
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// 记录解
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res.append(path)
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path.removeLast()
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return
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}
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preOrder(root: root.left)
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preOrder(root: root.right)
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@ -23,8 +23,6 @@ function preOrder(
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if (root.val === 7) {
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// 记录解
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res.push([...path]);
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path.pop();
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return;
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}
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preOrder(root.left, path, res);
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preOrder(root.right, path, res);
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@ -8,6 +8,6 @@
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!!! abstract
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数据结构的世界如同一睹厚实的砖墙。
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数据结构的世界如同一堵厚实的砖墙。
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数组的砖块整齐排列，逐个紧贴。链表的砖块分散各处，连接的藤蔓自由地穿梭于砖缝之间。
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@ -761,7 +761,7 @@
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[class]{}-[func]{backtrack}
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```
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根据题意，我们在找到值为 7 的节点后应该继续搜索，**因此需要将记录解之后的 `return` 语句删除**。下图对比了保留或删除 `return` 语句的搜索过程。
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根据题意，我们在找到值为 $7$ 的节点后应该继续搜索，**因此需要将记录解之后的 `return` 语句删除**。下图对比了保留或删除 `return` 语句的搜索过程。
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@ -776,7 +776,7 @@
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| 名词 | 定义 | 例题三 |
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| ------------------- | -------------------------------------------------------------------------- | -------------------------------------------------------------------- |
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| 解 Solution | 解是满足问题特定条件的答案，可能有一个或多个 | 根节点到节点 $7$ 的满足约束条件的所有路径 |
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| 约束条件 Constraint | 约束条件是问题中限制解的可行性的条件，通常用于剪枝 | 路径中不包含节点 $3$ ，只包含一个节点 $7$ |
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| 约束条件 Constraint | 约束条件是问题中限制解的可行性的条件，通常用于剪枝 | 路径中不包含节点 $3$ |
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| 状态 State | 状态表示问题在某一时刻的情况，包括已经做出的选择 | 当前已访问的节点路径，即 `path` 节点列表 |
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| 尝试 Attempt | 尝试是根据可用选择来探索解空间的过程，包括做出选择，更新状态，检查是否为解 | 递归访问左（右）子节点，将节点添加进 `path` ，判断节点的值是否为 $7$ |
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| 回退 Backtracking | 回退指遇到不满足约束条件的状态时，撤销前面做出的选择，回到上一个状态 | 当越过叶结点、结束结点访问、遇到值为 $3$ 的节点时终止搜索，函数返回 |
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