From c0980197c4a556757de72829b58b4efb6e5ae470 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=80=E6=96=87?=
 <30338551+YiwenXie@users.noreply.github.com>
Date: Wed, 12 May 2021 22:37:31 +0900
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200077.=E7=BB=84=E5=90=88.md?=
 =?UTF-8?q?=20Java=E7=89=88=E6=9C=AC?=
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---
 problems/0077.组合.md | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/problems/0077.组合.md b/problems/0077.组合.md
index 3dfb5216..f31766e0 100644
--- a/problems/0077.组合.md
+++ b/problems/0077.组合.md
@@ -340,6 +340,33 @@ public:
 
 
 Java：
+```java
+class Solution {
+    List<List<Integer>> result = new ArrayList<>();
+    LinkedList<Integer> path = new LinkedList<>();
+    public List<List<Integer>> combine(int n, int k) {
+        combineHelper(n, k, 1);
+        return result;
+    }
+
+    /**
+     * 每次从集合中选取元素，可选择的范围随着选择的进行而收缩，调整可选择的范围，就是要靠startIndex
+     * @param startIndex 用来记录本层递归的中，集合从哪里开始遍历（集合就是[1,...,n] ）。
+     */
+    private void combineHelper(int n, int k, int startIndex){
+        //终止条件
+        if (path.size() == k){
+            result.add(new ArrayList<>(path));
+            return;
+        }
+        for (int i = startIndex; i <= n - (k - path.size()) + 1; i++){
+            path.add(i);
+            combineHelper(n, k, i + 1);
+            path.removeLast();
+        }
+    }
+}
+```
 
 
 Python：