From 1c87243cb1f5d8ce096dbcfebbb247639c11f95f Mon Sep 17 00:00:00 2001
From: huangge1199 <huangge1199@hotmail.com>
Date: Mon, 2 Aug 2021 16:26:03 +0800
Subject: [PATCH] =?UTF-8?q?39:=E7=BB=84=E5=90=88=E6=80=BB=E5=92=8C?=
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 .../leetcode/editor/cn/CombinationSum.java    | 107 ++++++++++++++++++
 .../java/leetcode/editor/cn/CombinationSum.md |  53 +++++++++
 2 files changed, 160 insertions(+)
 create mode 100644 src/main/java/leetcode/editor/cn/CombinationSum.java
 create mode 100644 src/main/java/leetcode/editor/cn/CombinationSum.md

diff --git a/src/main/java/leetcode/editor/cn/CombinationSum.java b/src/main/java/leetcode/editor/cn/CombinationSum.java
new file mode 100644
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--- /dev/null
+++ b/src/main/java/leetcode/editor/cn/CombinationSum.java
@@ -0,0 +1,107 @@
+//给定一个无重复元素的正整数数组 candidates 和一个正整数 target ，找出 candidates 中所有可以使数字和为目标数 target 的
+//唯一组合。 
+//
+// candidates 中的数字可以无限制重复被选取。如果至少一个所选数字数量不同，则两种组合是唯一的。 
+//
+// 对于给定的输入，保证和为 target 的唯一组合数少于 150 个。 
+//
+// 
+//
+// 示例 1： 
+//
+// 
+//输入: candidates = [2,3,6,7], target = 7
+//输出: [[7],[2,2,3]]
+// 
+//
+// 示例 2： 
+//
+// 
+//输入: candidates = [2,3,5], target = 8
+//输出: [[2,2,2,2],[2,3,3],[3,5]] 
+//
+// 示例 3： 
+//
+// 
+//输入: candidates = [2], target = 1
+//输出: []
+// 
+//
+// 示例 4： 
+//
+// 
+//输入: candidates = [1], target = 1
+//输出: [[1]]
+// 
+//
+// 示例 5： 
+//
+// 
+//输入: candidates = [1], target = 2
+//输出: [[1,1]]
+// 
+//
+// 
+//
+// 提示： 
+//
+// 
+// 1 <= candidates.length <= 30 
+// 1 <= candidates[i] <= 200 
+// candidate 中的每个元素都是独一无二的。 
+// 1 <= target <= 500 
+// 
+// Related Topics 数组 回溯 
+// 👍 1458 👎 0
+
+package leetcode.editor.cn;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+//39:组合总和
+public class CombinationSum {
+    public static void main(String[] args) {
+        //测试代码
+        Solution solution = new CombinationSum().new Solution();
+        solution.combinationSum(new int[]{2, 3, 6, 7}, 7);
+    }
+
+    //力扣代码
+    //leetcode submit region begin(Prohibit modification and deletion)
+    class Solution {
+        List<List<Integer>> list = new ArrayList<>();
+        boolean bl = false;
+
+        public List<List<Integer>> combinationSum(int[] candidates, int target) {
+            Arrays.sort(candidates);
+            backtrack(candidates, 0, new ArrayList<>(), 0, target);
+            return list;
+        }
+
+        private void backtrack(int[] candidates, int index, List<Integer> use, int sum, int target) {
+            if (sum == target) {
+                list.add(new ArrayList<>(use));
+                bl = true;
+                return;
+            }
+            if (sum > target) {
+                bl = true;
+                return;
+            }
+
+            for (int i = index; i < candidates.length; i++) {
+                use.add(candidates[i]);
+                backtrack(candidates, i, use, sum + candidates[i], target);
+                use.remove(use.size() - 1);
+                if(bl){
+                    break;
+                }
+            }
+            bl = false;
+        }
+    }
+//leetcode submit region end(Prohibit modification and deletion)
+
+}
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diff --git a/src/main/java/leetcode/editor/cn/CombinationSum.md b/src/main/java/leetcode/editor/cn/CombinationSum.md
new file mode 100644
index 0000000..ca6b7e9
--- /dev/null
+++ b/src/main/java/leetcode/editor/cn/CombinationSum.md
@@ -0,0 +1,53 @@
+<p>给定一个<strong>无重复元素</strong>的正整数数组 <code>candidates</code> 和一个正整数 <code>target</code> ，找出 <code>candidates</code> 中所有可以使数字和为目标数 <code>target</code> 的唯一组合。</p>
+
+<p><code>candidates</code> 中的数字可以无限制重复被选取。如果至少一个所选数字数量不同，则两种组合是唯一的。 </p>
+
+<p>对于给定的输入，保证和为 <code>target</code> 的唯一组合数少于 <code>150</code> 个。</p>
+
+<p> </p>
+
+<p><strong>示例 1：</strong></p>
+
+<pre>
+<strong>输入: </strong>candidates = <code>[2,3,6,7], </code>target = <code>7</code>
+<strong>输出: </strong>[[7],[2,2,3]]
+</pre>
+
+<p><strong>示例 2：</strong></p>
+
+<pre>
+<strong>输入: </strong>candidates = [2,3,5]<code>, </code>target = 8
+<strong>输出: </strong>[[2,2,2,2],[2,3,3],[3,5]]</pre>
+
+<p><strong>示例 3：</strong></p>
+
+<pre>
+<strong>输入: </strong>candidates = <code>[2], </code>target = 1
+<strong>输出: </strong>[]
+</pre>
+
+<p><strong>示例 4：</strong></p>
+
+<pre>
+<strong>输入: </strong>candidates = <code>[1], </code>target = <code>1</code>
+<strong>输出: </strong>[[1]]
+</pre>
+
+<p><strong>示例 5：</strong></p>
+
+<pre>
+<strong>输入: </strong>candidates = <code>[1], </code>target = <code>2</code>
+<strong>输出: </strong>[[1,1]]
+</pre>
+
+<p> </p>
+
+<p><strong>提示：</strong></p>
+
+<ul>
+	<li><code>1 <= candidates.length <= 30</code></li>
+	<li><code>1 <= candidates[i] <= 200</code></li>
+	<li><code>candidate</code> 中的每个元素都是独一无二的。</li>
+	<li><code>1 <= target <= 500</code></li>
+</ul>
+<div><div>Related Topics</div><div><li>数组</li><li>回溯</li></div></div>\n<div><li>👍 1458</li><li>👎 0</li></div>
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