solve: word search

Author: tolluset

word-search/tolluset.ts

@@ -0,0 +1,83 @@
+/*
+ * TC: O(row * column * 4^words.length)
+ * SC: O(n)
+ * */
+function exist(board: string[][], word: string): boolean {
+  const words = word.split("");
+  const n = words.length;
+
+  const rowLen = board.length;
+  const columnLen = board[0].length;
+
+  const dfs = (row: number, column: number, cursor: number) => {
+    if (cursor === n) {
+      return true;
+    }
+
+    if (
+      row < 0 ||
+      row >= rowLen ||
+      column < 0 ||
+      column >= columnLen ||
+      board[row][column] !== words[cursor]
+    ) {
+      return false;
+    }
+
+    const current = board[row][column];
+    board[row][column] = "";
+
+    if (
+      dfs(row - 1, column, cursor + 1) ||
+      dfs(row + 1, column, cursor + 1) ||
+      dfs(row, column - 1, cursor + 1) ||
+      dfs(row, column + 1, cursor + 1)
+    ) {
+      return true;
+    }
+
+    board[row][column] = current;
+
+    return false;
+  };
+
+  for (let row = 0; row < rowLen; row++) {
+    for (let column = 0; column < columnLen; column++) {
+      if (dfs(row, column, 0)) {
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+const t1 = exist(
+  [
+    ["A", "B", "C", "E"],
+    ["S", "F", "C", "S"],
+    ["A", "D", "E", "E"],
+  ],
+  "ABCCED",
+);
+console.info("🚀 : tolluset.ts:5: t1=", t1); // true
+
+const t2 = exist(
+  [
+    ["A", "B", "C", "E"],
+    ["S", "F", "C", "S"],
+    ["A", "D", "E", "E"],
+  ],
+  "SEE",
+);
+console.info("🚀 : tolluset.ts:15: t2=", t2); // true
+
+const t3 = exist(
+  [
+    ["A", "B", "C", "E"],
+    ["S", "F", "C", "S"],
+    ["A", "D", "E", "E"],
+  ],
+  "ABCB",
+);
+console.info("🚀 : tolluset.ts:24: t3=", t3); // false