0077.组合、0077.组合优化：Swift实现减少参数

problems/0077.组合.md

@@ -627,7 +627,7 @@ int** combine(int n, int k, int* returnSize, int** returnColumnSizes){
 func combine(_ n: Int, _ k: Int) -> [[Int]] {
     var path = [Int]()
     var result = [[Int]]()
-    func backtracking(_ n: Int, _ k: Int, _ startIndex: Int) {
+    func backtracking(start: Int) {
         // 结束条件，并收集结果
         if path.count == k {
             result.append(path)
@@ -638,15 +638,15 @@ func combine(_ n: Int, _ k: Int) -> [[Int]] {
         // let end = n
         // 剪枝优化
         let end = n - (k - path.count) + 1
-        guard startIndex <= end else { return }
-        for i in startIndex ... end {
+        guard start <= end else { return }
+        for i in start ... end {
             path.append(i) // 处理结点
-            backtracking(n, k, i + 1) // 递归
+            backtracking(start: i + 1) // 递归
             path.removeLast() // 回溯
         }
     }
 
-    backtracking(n, k, 1)
+    backtracking(start: 1)
     return result
 }
 ```

problems/0077.组合优化.md

@@ -300,7 +300,7 @@ Swift：
 func combine(_ n: Int, _ k: Int) -> [[Int]] {
     var path = [Int]()
     var result = [[Int]]()
-    func backtracking(_ n: Int, _ k: Int, _ startIndex: Int) {
+    func backtracking(start: Int) {
         // 结束条件，并收集结果
         if path.count == k {
             result.append(path)
@@ -311,15 +311,15 @@ func combine(_ n: Int, _ k: Int) -> [[Int]] {
         // let end = n
         // 剪枝优化
         let end = n - (k - path.count) + 1
-        guard startIndex <= end else { return }
-        for i in startIndex ... end {
+        guard start <= end else { return }
+        for i in start ... end {
             path.append(i) // 处理结点
-            backtracking(n, k, i + 1) // 递归
+            backtracking(start: i + 1) // 递归
             path.removeLast() // 回溯
         }
     }
 
-    backtracking(n, k, 1)
+    backtracking(start: 1)
     return result
 }
 ```