@@ -502,5 +502,35 @@ func combinationSum(_ candidates: [Int], _ target: Int) -> [[Int]] {
502502}
503503```
504504
505+ ## Scala
506+ 507+ ``` scala
508+ object Solution {
509+ import scala .collection .mutable
510+ def combinationSum (candidates : Array [Int ], target : Int ): List [List [Int ]] = {
511+ var result = mutable.ListBuffer [List [Int ]]()
512+ var path = mutable.ListBuffer [Int ]()
513+ 514+ def backtracking (sum : Int , index : Int ): Unit = {
515+ if (sum == target) {
516+ result.append(path.toList) // 如果正好等于target,就添加到结果集
517+ return
518+ }
519+ // 应该是从当前索引开始的,而不是从0
520+ // 剪枝优化:添加循环守卫,当sum + c(i) <= target的时候才循环,才可以进入下一次递归
521+ for (i <- index until candidates.size if sum + candidates(i) <= target) {
522+ path.append(candidates(i))
523+ backtracking(sum + candidates(i), i)
524+ path = path.take(path.size - 1 )
525+ }
526+ }
527+ 528+ backtracking(0 , 0 )
529+ result.toList
530+ }
531+ }
532+ ```
533+ 534+ 505535-----------------------
506536<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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