Time: 3 ms (91.93%), Space: 48.9 MB (42.67%) - LeetHub

Author: hajin-kim

0036-valid-sudoku/0036-valid-sudoku.kt

@@ -0,0 +1,71 @@
+class Solution {
+    private fun BooleanArray.clear() {
+        for (i in indices) {
+            this[i] = false
+        }
+    }
+
+    fun isValidSudoku(board: Array<CharArray>): Boolean {
+        val isFilled = BooleanArray(10)
+
+        for (row in board) {
+            isFilled.clear()
+
+            for (char in row) {
+                if (char == '.') {
+                    continue
+                }
+
+                val number = char.digitToInt()
+                if (isFilled[number]) {
+                    return false
+                }
+                isFilled[number] = true
+            }
+        }
+
+        for (x in 0 until 9) {
+            isFilled.clear()
+
+            for (y in 0 until 9) {
+                val char = board[y][x]
+
+                if (char == '.') {
+                    continue
+                }
+
+                val number = char.digitToInt()
+                if (isFilled[number]) {
+                    return false
+                }
+                isFilled[number] = true
+            }
+        }
+
+        for (gridY in 0 until 3) {
+            for (gridX in 0 until 3) {
+                isFilled.clear()
+                
+                val startY = gridY * 3
+                val startX = gridX * 3
+                for (y in startY until startY + 3) {
+                    for (x in startX until startX + 3) {
+                        val char = board[y][x]
+
+                        if (char == '.') {
+                            continue
+                        }
+
+                        val number = char.digitToInt()
+                        if (isFilled[number]) {
+                            return false
+                        }
+                        isFilled[number] = true
+                    }
+                }
+            }
+        }
+        
+        return true
+    }
+}