adding Problem 37

通过leetcode的测试

Author: aQua

Algorithms/0037.sudoku-solver/README.md

@@ -16,7 +16,8 @@ A sudoku puzzle...
 ...and its solution numbers marked in red.
 
 ## 解题思路
-
+我把数独框中，需要保证数字不重复的3×3小块，称为一个block。
+由于数独需要保持每行，每列，每个block中的数字不重复。
 
 ## 总结
 

Algorithms/0037.sudoku-solver/sudoku-solver.go

@@ -2,22 +2,26 @@ package Problem0037
 
 func solveSudoku(board [][]byte) {
 	nums := []byte("123456789")
-	blocks := []int{1, 3, 5, 7, 0, 8, 4, 2, 6}
-	for _, n := range nums {
-		if !fillBlock(board, n, blocks) {
-			panic("此题无解")
-		}
+	blocks := []int{0, 1, 2, 3, 4, 5, 6, 7, 8}
+
+	if !fillBlock(board, nums, blocks) {
+		panic("此题无解")
 	}
 }
 
-func fillBlock(board [][]byte, n byte, blocks []int) bool {
+func fillBlock(board [][]byte, nums []byte, blocks []int) bool {
 	if len(blocks) == 0 {
 		return true
 	}
+	if len(nums) == 0 {
+		return fillBlock(board, []byte("123456789"), blocks[1:])
+	}
 
 	block := blocks[0]
+	n := nums[0]
+	nums = nums[1:]
 
-	print(board, n, block)
+	// print(board, n, block)
 
 	rowZero := (block / 3) * 3
 	colZero := (block % 3) * 3
@@ -35,9 +39,9 @@ func fillBlock(board [][]byte, n byte, blocks []int) bool {
 	}
 
 	if had() {
-		return fillBlock(board, n, blocks[1:])
+		return fillBlock(board, nums, blocks)
 	}
-	// 检查(r,c)所在的行和列是否已经存在 b 了
+	// 检查(r,c)所在的行和列是否已经存在 n 了
 	isClear := func(r, c int) bool {
 		for i := 0; i < 9; i++ {
 			if board[r][i] == n || board[i][c] == n {
@@ -51,12 +55,12 @@ func fillBlock(board [][]byte, n byte, blocks []int) bool {
 		for c := colZero; c < colZero+3; c++ {
 			if board[r][c] == '.' && isClear(r, c) {
 				board[r][c] = n
-				if fillBlock(board, n, blocks[1:]) {
+				if fillBlock(board, nums, blocks) {
 					return true
 				}
 				// 后面的填写不成功，所以需要还原这个格子
 				board[r][c] = '.'
-				print(board, n, block)
+				// print(board, n, block)
 			}
 		}
 	}