Create 212.cpp
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1126c4062a
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ca6c433e9c
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class Trie {
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public:
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struct Node
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{
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bool ends;
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string word;
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Node* next[26];
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Node()
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{
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ends = false;
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memset(next, 0, sizeof(next));
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}
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};
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Node* root;
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Trie() {
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root = new Node;
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}
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inline void stepDownInsert(const string& word, int index, Node* current) {
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if (index >= word.size()) {
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current->ends = true;
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current->word = word;
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return;
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}
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if (!current->next[word[index] - 'a']) {
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auto n = new Node;
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current->next[word[index] - 'a'] = n;
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}
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stepDownInsert(word, index + 1, current->next[word[index] - 'a']);
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}
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void insert(string word) {
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stepDownInsert(word, 0, root);
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}
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inline bool stepDownSearch(const string& word, int index, Node* current) {
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if (index >= word.size()) return current->ends;
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if (current->next[word[index] - 'a']) return stepDownSearch(word, index + 1, current->next[word[index] - 'a']);
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return false;
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}
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bool search(string word) {
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return stepDownSearch(word, 0, root);
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}
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inline bool stepDownPrefix(const string& word, int index, Node* current) {
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if (index >= word.size()) return true;
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if (current->next[word[index] - 'a']) return stepDownPrefix(word, index + 1, current->next[word[index] - 'a']);
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return false;
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}
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bool startsWith(string prefix) {
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return stepDownPrefix(prefix, 0, root);
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}
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};
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class Solution {
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public:
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Trie t;
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void stepDownFind(vector<vector<char>>& board, vector<vector<bool>>& visited, unordered_set<string>& found, int line, int col, Trie::Node* current) {
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if (current->ends) {
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found.insert(current->word);
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}
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// go up
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if (line > 0 && !visited[line - 1][col] && current->next[board[line-1][col] - 'a']) {
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visited[line - 1][col] = true;
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stepDownFind(board, visited, found, line - 1, col, current->next[board[line - 1][col] - 'a']);
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visited[line - 1][col] = false;
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}
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// go down
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if (line < board.size() - 1 && !visited[line + 1][col] && current->next[board[line + 1][col] - 'a']) {
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visited[line + 1][col] = true;
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stepDownFind(board, visited, found, line + 1, col, current->next[board[line + 1][col] - 'a']);
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visited[line + 1][col] = false;
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}
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// go left
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if (col > 0 && !visited[line][col - 1] && current->next[board[line][col - 1] - 'a']) {
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visited[line][col - 1] = true;
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stepDownFind(board, visited, found, line, col - 1, current->next[board[line][col - 1] - 'a']);
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visited[line][col - 1] = false;
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}
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// go right
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if (col < board[line].size() - 1 && !visited[line][col + 1] && current->next[board[line][col + 1] - 'a']) {
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visited[line][col + 1] = true;
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stepDownFind(board, visited, found, line, col + 1, current->next[board[line][col + 1] - 'a']);
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visited[line][col + 1] = false;
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}
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}
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vector<string> findWords(vector<vector<char>>& board, vector<string>& words) {
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for (auto& word : words) {
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t.insert(word);
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}
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vector<vector<bool>> visited;
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for (int i = 0; i < board.size(); i++)
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{
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visited.emplace_back(board[i].size(), false);
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}
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unordered_set<string> found;
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for (int line = 0; line < board.size(); line++) {
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for (int col = 0; col < board[line].size(); col++) {
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if (t.root->next[board[line][col] - 'a']) {
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visited[line][col] = true;
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stepDownFind(board, visited, found, line, col, t.root->next[board[line][col] - 'a']);
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visited[line][col] = false;
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}
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}
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}
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return vector<string>(found.begin(), found.end());
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}
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};
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