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#include "leetcode.h"
struct Trie {
bool isEnd;
string word;
Trie *child[26];
Trie() {
isEnd = false;
word = "";
for (int i = 0; i < 26; i++)
child[i] = NULL;
}
};
class Solution {
public:
vector<string> ans;
vector<string> findWords(vvd(char) & board, vector<string> &words) {
int n = board.size(), m = board[0].size();
for (auto w : words)
insert(w);
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
dfs(board, i, j, n, m, root);
return ans;
}
private:
vector<int> dx = {-1, 0, 1, 0}, dy = {0, 1, 0, -1};
Trie *root = new Trie();
void insert(string &s) {
int n = s.size();
Trie *curr = root;
for (int i = 0; i < n; i++) {
int idx = s[i] - 'a';
if (curr->child[idx] == NULL)
curr->child[idx] = new Trie();
curr = curr->child[idx];
}
curr->isEnd = true;
curr->word = s;
}
void dfs(vvd(char) & board, int i, int j, int n, int m, Trie *curr) {
if (i < 0 || i >= n || j < 0 || j >= m || board[i][j] == '#')
return;
int idx = board[i][j] - 'a';
if (curr->child[idx] == NULL)
return;
curr = curr->child[idx];
if (curr->isEnd) {
ans.push_back(curr->word);
curr->isEnd = false;
}
char val = board[i][j];
board[i][j] = '#';
for (int k = 0; k < 4; k++) {
int newI = i + dx[k], newJ = j + dy[k];
dfs(board, newI, newJ, n, m, curr);
}
board[i][j] = val;
}
};
int main() {
Solution obj;
vvd(char) board = {{'a', 'b'}, {'c', 'd'}};
vector<string> words = {"abcb"};
for (auto i : obj.findWords(board, words))
cout << i << endl;
}
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