word search sol

Author: dylan-jung

word-search/dylan-jung.cpp

@@ -0,0 +1,40 @@
+class Solution {
+public:
+    vector<vector<char>> g_board;
+    int m, n;
+    int dx[4] = { -1, 1, 0, 0 };
+    int dy[4] = { 0, 0, -1, 1 };
+    bool visited[6][6];
+
+    bool hasWord(string word, int idx, int r, int c) {
+        if(idx >= word.size()) return true;
+        if(!(0 <= r && r < n && 0 <= c && c < m)) return false;
+        if(g_board[r][c] != word[idx]) return false;
+        if(visited[r][c]) return false;
+        visited[r][c] = true;
+        // cout << r << " " << c << " " << word[idx] << "\n";
+        for(int i = 0; i < 4; i++) {
+            int nr = r + dx[i];
+            int nc = c + dy[i];
+            if(hasWord(word, idx+1, nr, nc))
+                return true;
+        }
+        visited[r][c] = false;
+        return false;
+    }
+
+    bool exist(vector<vector<char>>& board, string word) {
+        g_board = board;
+        n = board.size();
+        m = board[0].size();
+        for(int i = 0; i < n; i++) {
+            for(int j = 0; j < m; j++) {
+                if(g_board[i][j] == word[0]) {
+                    fill(&visited[0][0], &visited[0][0]+36, false);
+                    if(hasWord(word, 0, i, j)) return true;
+                }
+            }
+        }
+        return false;
+    }
+};