solve: word search

Author: wogha95

word-search/wogha95.js

@@ -0,0 +1,51 @@
+// TC: O(M * N * 4^W)
+// SC: O(MIN)
+// W: word.length, MIN: min(M * N, W)
+
+/**
+ * @param {character[][]} board
+ * @param {string} word
+ * @return {boolean}
+ */
+var exist = function (board, word) {
+  let result = false;
+
+  for (let r = 0; r < board.length; r++) {
+    for (let c = 0; c < board[0].length; c++) {
+      dfs(r, c, 0);
+    }
+  }
+
+  return result;
+
+  function dfs(row, column, wordIndex) {
+    if (!isValid(row, column)) {
+      return;
+    }
+    if (board[row][column] !== word[wordIndex]) {
+      return;
+    }
+    if (wordIndex === word.length - 1) {
+      result = true;
+      return;
+    }
+
+    const temp = board[row][column];
+    board[row][column] = "#";
+    dfs(row + 1, column, wordIndex + 1);
+    dfs(row - 1, column, wordIndex + 1);
+    dfs(row, column + 1, wordIndex + 1);
+    dfs(row, column - 1, wordIndex + 1);
+    board[row][column] = temp;
+  }
+
+  function isValid(row, column) {
+    if (row < 0 || board.length <= row) {
+      return false;
+    }
+    if (column < 0 || board[0].length <= column) {
+      return false;
+    }
+    return true;
+  }
+};