diff --git a/lib/isValidSudoku/isValidSudoku.ts b/lib/isValidSudoku/isValidSudoku.ts
index bf68845..119c94c 100644
--- a/lib/isValidSudoku/isValidSudoku.ts
+++ b/lib/isValidSudoku/isValidSudoku.ts
@@ -1,17 +1,25 @@
 export function isValidSudoku(board: string[][]): boolean {
-  const rowTable: Record<string, string[]> = {}
-  const colTable: Record<string, string[]> = {}
-  const cellTable: Record<string, string[]> = {}
+  const N = board.length;
+  const rows = new Set();
+  const colls = new Set();
+  const cells = new Set();
 
-  for (let i = 0; i < board.length; i++) {
-    rowTable[i] = board[i].filter(item => item !== ".");
-    if (new Set(rowTable[i]).size !== rowTable[i].length) return false;
-    colTable[i] = board.map(item => item[i]).filter(item => item !== ".");
-    if (new Set(colTable[i]).size !== rowTable[i].length) return false;
-  }
+  for (let i = 0; i < N; i++) {
+    for (let j = 0; j < N; j++) {
+      const val = board[i][j];
+      if (val === ".") continue;
+      const cellIndex = Math.floor(i / 3) * 3 + Math.floor(j / 3);
+      const rowKey = i + "_" + val;
+      const collKey = j + "_" + val;
+      const cellKey = cellIndex + "_" + val;
 
+      if (rows.has(rowKey) || colls.has(collKey) || cells.has(cellKey)) return false;
 
-  console.log({ cellTable, rowTable, colTable })
+      rows.add(rowKey);
+      colls.add(collKey);
+      cells.add(cellKey);
+    }
+  }
 
   return true
 };