@@ -602,5 +602,100 @@ func solveSudoku(_ board: inout [[Character]]) {
602602}
603603```
604604
605+ ### Scala
606+ 607+ 详细写法:
608+ ``` scala
609+ object Solution {
610+ 611+ def solveSudoku (board : Array [Array [Char ]]): Unit = {
612+ backtracking(board)
613+ }
614+ 615+ def backtracking (board : Array [Array [Char ]]): Boolean = {
616+ for (i <- 0 until 9 ) {
617+ for (j <- 0 until 9 ) {
618+ if (board(i)(j) == '.' ) { // 必须是为 . 的数字才放数字
619+ for (k <- '1' to '9' ) { // 这个位置放k是否合适
620+ if (isVaild(i, j, k, board)) {
621+ board(i)(j) = k
622+ if (backtracking(board)) return true // 找到了立刻返回
623+ board(i)(j) = '.' // 回溯
624+ }
625+ }
626+ return false // 9个数都试完了,都不行就返回false
627+ }
628+ }
629+ }
630+ true // 遍历完所有的都没返回false,说明找到了
631+ }
632+ 633+ def isVaild (x : Int , y : Int , value : Char , board : Array [Array [Char ]]): Boolean = {
634+ // 行
635+ for (i <- 0 until 9 ) {
636+ if (board(i)(y) == value) {
637+ return false
638+ }
639+ }
640+ 641+ // 列
642+ for (j <- 0 until 9 ) {
643+ if (board(x)(j) == value) {
644+ return false
645+ }
646+ }
647+ 648+ // 宫
649+ var row = (x / 3 ) * 3
650+ var col = (y / 3 ) * 3
651+ for (i <- row until row + 3 ) {
652+ for (j <- col until col + 3 ) {
653+ if (board(i)(j) == value) {
654+ return false
655+ }
656+ }
657+ }
658+ 659+ true
660+ }
661+ }
662+ ```
663+ 664+ 遵循Scala至简原则写法:
665+ ``` scala
666+ object Solution {
667+ 668+ def solveSudoku (board : Array [Array [Char ]]): Unit = {
669+ backtracking(board)
670+ }
671+ 672+ def backtracking (board : Array [Array [Char ]]): Boolean = {
673+ // 双重for循环 + 循环守卫
674+ for (i <- 0 until 9 ; j <- 0 until 9 if board(i)(j) == '.' ) {
675+ // 必须是为 . 的数字才放数字,使用循环守卫判断该位置是否可以放置当前循环的数字
676+ for (k <- '1' to '9' if isVaild(i, j, k, board)) { // 这个位置放k是否合适
677+ board(i)(j) = k
678+ if (backtracking(board)) return true // 找到了立刻返回
679+ board(i)(j) = '.' // 回溯
680+ }
681+ return false // 9个数都试完了,都不行就返回false
682+ }
683+ true // 遍历完所有的都没返回false,说明找到了
684+ }
685+ 686+ def isVaild (x : Int , y : Int , value : Char , board : Array [Array [Char ]]): Boolean = {
687+ // 行,循环守卫进行判断
688+ for (i <- 0 until 9 if board(i)(y) == value) return false
689+ // 列,循环守卫进行判断
690+ for (j <- 0 until 9 if board(x)(j) == value) return false
691+ // 宫,循环守卫进行判断
692+ var row = (x / 3 ) * 3
693+ var col = (y / 3 ) * 3
694+ for (i <- row until row + 3 ; j <- col until col + 3 if board(i)(j) == value) return false
695+ true // 最终没有返回false,就说明该位置可以填写true
696+ }
697+ }
698+ ```
699+ 605700-----------------------
606701<div align =" center " ><img src =https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width =500 > </img ></div >
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