Jul 6, 2022 · May 31, 2022 · May 31, 2022 · Jun 1, 2022 · Jun 1, 2022 · Jun 1, 2022
diff --git a/problems/0077.组合.md b/problems/0077.组合.md
diff --git a/problems/0077.组合优化.md b/problems/0077.组合优化.md
Original file line number	Diff line number	Diff line change
Expand Up		@@ -673,5 +673,63 @@ func combine(_ n: Int, _ k: Int) -> [[Int]] {
		}
		```

	### Scala

	暴力:
	```scala
	object Solution {
	import scala.collection.mutable // 导包
	def combine(n: Int, k: Int): List[List[Int]] = {
	var result = mutable.ListBuffer[List[Int]]() // 存放结果集
	var path = mutable.ListBuffer[Int]() //存放符合条件的结果

	def backtracking(n: Int, k: Int, startIndex: Int): Unit = {
	if (path.size == k) {
	// 如果path的size == k就达到题目要求,添加到结果集,并返回
	result.append(path.toList)
	return
	}
	for (i <- startIndex to n) { // 遍历从startIndex到n
	path.append(i) // 先把数字添加进去
	backtracking(n, k, i + 1) // 进行下一步回溯
	path = path.take(path.size - 1) // 回溯完再删除掉刚刚添加的数字
	}
	}

	backtracking(n, k, 1) // 执行回溯
	result.toList // 最终返回result的List形式,return关键字可以省略
	}
	}
	```

	剪枝:

	```scala
	object Solution {
	import scala.collection.mutable // 导包
	def combine(n: Int, k: Int): List[List[Int]] = {
	var result = mutable.ListBuffer[List[Int]]() // 存放结果集
	var path = mutable.ListBuffer[Int]() //存放符合条件的结果

	def backtracking(n: Int, k: Int, startIndex: Int): Unit = {
	if (path.size == k) {
	// 如果path的size == k就达到题目要求,添加到结果集,并返回
	result.append(path.toList)
	return
	}
	// 剪枝优化
	for (i <- startIndex to (n - (k - path.size) + 1)) {
	path.append(i) // 先把数字添加进去
	backtracking(n, k, i + 1) // 进行下一步回溯
	path = path.take(path.size - 1) // 回溯完再删除掉刚刚添加的数字
	}
	}

	backtracking(n, k, 1) // 执行回溯
	result.toList // 最终返回result的List形式,return关键字可以省略
	}
	}
	```

		-----------------------
		<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>
Original file line number	Diff line number	Diff line change
Expand Up		@@ -346,5 +346,34 @@ func combine(_ n: Int, _ k: Int) -> [[Int]] {
		}
		```

	Scala:

	```scala
	object Solution {
	import scala.collection.mutable // 导包
	def combine(n: Int, k: Int): List[List[Int]] = {
	var result = mutable.ListBuffer[List[Int]]() // 存放结果集
	var path = mutable.ListBuffer[Int]() //存放符合条件的结果

	def backtracking(n: Int, k: Int, startIndex: Int): Unit = {
	if (path.size == k) {
	// 如果path的size == k就达到题目要求,添加到结果集,并返回
	result.append(path.toList)
	return
	}
	// 剪枝优化
	for (i <- startIndex to (n - (k - path.size) + 1)) {
	path.append(i) // 先把数字添加进去
	backtracking(n, k, i + 1) // 进行下一步回溯
	path = path.take(path.size - 1) // 回溯完再删除掉刚刚添加的数字
	}
	}

	backtracking(n, k, 1) // 执行回溯
	result.toList // 最终返回result的List形式,return关键字可以省略
	}
	}
	```

		-----------------------
		<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>