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Commit c5b210f

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‎README.md‎

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@@ -111,8 +111,9 @@ continually updating 😃.
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* [111. Minimum Depth of Binary Tree](src/0111_minimum_depth_of_binary_tree/minimum_depth_of_binary_tree.go)   *`binary tree;`*   *`dfs`*
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* [112. Path Sum](src/0112_path_sum/path_sum.go)   *`binary tree;`*   *`dfs`*
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* [144. Binary Tree Preorder Traversal](src/0144_binary_tree_preorder_traversal/binary_tree_preorder_traversal.go)   *`binary tree;`*   *`pre-order traversal`*
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* [226. Invert Binary Tree](src/0226_invert_binary_tree/invert_binary_tree.go)   *`binary tree;`*
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* [235. Lowest Common Ancestor of a Binary Search Tree](src/0235_lowest_common_ancestor_of_a_binary_search_tree/lcaoabst.go)   *`binary tree;`*
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* [208. Implement Trie (Prefix Tree)](src/0208_implement_trie_prefix_tree/impltrie.go)   *`trie`*
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* [226. Invert Binary Tree](src/0226_invert_binary_tree/invert_binary_tree.go)   *`binary tree`*
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* [235. Lowest Common Ancestor of a Binary Search Tree](src/0235_lowest_common_ancestor_of_a_binary_search_tree/lcaoabst.go)   *`binary tree`*
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* [257. Binary Tree Paths](src/0257_binary_tree_paths/binary_tree_paths.go)   *`binary tree`*
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* [307. Range Sum Query - Mutable](src/0307_Range_Sum_Query_Mutable/range_sum_query_mut.go)   *`segment tree`*
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* [404. Sum of Left Leaves](src/0404_sum_of_left_leaves/sum_of_left_leaves.go)   *`binary tree`*
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/*
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208. Implement Trie (Prefix Tree)
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https://leetcode.com/problems/implement-trie-prefix-tree/
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Implement a trie with insert, search, and startsWith methods.
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Note:
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You may assume that all inputs are consist of lowercase letters a-z.
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All inputs are guaranteed to be non-empty strings.
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*/
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// time: 2019年01月31日
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package impltree
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type node struct {
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isWord bool
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next map[byte]*node
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}
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// Trie prefix tree
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type Trie struct {
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root *node
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size int
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}
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// Constructor initialize data structure here.
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func Constructor() Trie {
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return Trie{root: &node{next: make(map[byte]*node)}}
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}
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// Insert inserts a word into the trie.
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func (trie *Trie) Insert(word string) {
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cur := trie.root
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for i := 0; i < len(word); i++ {
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if _, ok := cur.next[word[i]]; !ok {
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cur.next[word[i]] = &node{next: make(map[byte]*node)}
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}
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cur, _ = cur.next[word[i]]
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}
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if !cur.isWord {
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cur.isWord = true
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trie.size++
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}
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}
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// Search returns if the word is the trie.
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func (trie *Trie) Search(word string) bool {
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cur := trie.root
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for i := 0; i < len(word); i++ {
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if _, ok := cur.next[word[i]]; !ok {
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return false
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}
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cur, _ = cur.next[word[i]]
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}
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return cur.isWord
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}
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// StartsWith returns if there is any word in the trie that starts with the given prefix.
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func (trie *Trie) StartsWith(prefix string) bool {
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cur := trie.root
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for i := 0; i < len(prefix); i++ {
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if _, ok := cur.next[prefix[i]]; !ok {
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return false
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}
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cur, _ = cur.next[prefix[i]]
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}
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return true
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}
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package impltree
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import "testing"
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func TestImplTrie(t *testing.T) {
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trie := Constructor()
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trie.Insert("apple")
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for i, j := range map[string]bool{"apple": true, "app": false} {
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if res := trie.Search(i); res != j {
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t.Errorf("expected %t, got %t", j, res)
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}
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}
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for i, j := range map[string]bool{"app": true, "as": false} {
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if res := trie.StartsWith(i); res != j {
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t.Errorf("expected %t, got %t", j, res)
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}
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}
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trie.Insert("app")
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if res := trie.Search("app"); res != true {
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t.Errorf("expected %t, got %t", true, res)
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}
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}

‎src/README.md‎

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|0200|[200. Number of Islands](0200_number_of_island/number_of_island.go)|Medium|*`dfs;`* *`bfs`*|
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|0203|[203. Remove Linked List Elements](0203_remove_linked_list_elements/remove_linked_list_elements.go)|Easy|*`linked list`*|
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|0206|[206. Reverse Linked List](0206_reverse_linked_list/reverse_linked_list.go)|Easy|*`linked list`*|
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|0208|[208. Implement Trie (Prefix Tree)](0208_implement_trie_prefix_tree/impltrie.go)|Medium|*`trie`*|
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|0209|[Minimum Size Subarray Sum](./0209_minimum_size_subarray_sum/minimum_size_subarray_sum.go)|Medium|*`sliding window`*|
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|0215|[215. Kth Largest Element in an Array](0215_kth_largest_element_in_an_array/kthleiaa.go)|Medium|*`sort`*|
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|0217|[217. Contains Duplicate](0217_contains_duplicate/contains_duplicate.go)|Easy|*`map`*|

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