添加题46，47

Author: ligecarryme

算法思维/回溯法.md

@@ -68,4 +68,82 @@ function helper(i: number, nums: number[], res: number[][], tmp: number[]): void
 
 ##### [46. 全排列](https://leetcode-cn.com/problems/permutations/)
 
-给定一个不含重复数字的数组 `nums` ，返回其 **所有可能的全排列** 。你可以 **按任意顺序** 返回答案。
+给定一个不含重复数字的数组 `nums` ，返回其 **所有可能的全排列** 。你可以 **按任意顺序** 返回答案。
+
+```tsx
+function permute(nums: number[]): number[][] {
+    const res: number[][] = []
+    const templist: number[] = []
+    const visited: boolean[] = new Array(nums.length).fill(false)
+    backTrack(nums, res, templist, visited)
+    return res
+};
+
+function backTrack(nums, res, templist, visited) {
+    if (templist.length === nums.length) {
+        res.push([].concat(templist))
+        return
+    }
+    for (let i = 0; i < nums.length; i++) {
+        if (visited[i]) {
+            continue
+        }
+        templist.push(nums[i])
+        visited[i] = true
+        backTrack(nums, res, templist, visited)
+        visited[i] = false
+        templist.pop(nums[i])
+    }
+}
+```
+
+##### [47. 全排列 II](https://leetcode-cn.com/problems/permutations-ii/)
+
+给定一个可包含重复数字的序列 `nums` ，**按任意顺序** 返回所有不重复的全排列。
+
+```tsx
+function permuteUnique(nums: number[]): number[][] {
+    nums = nums.sort((a, b) => a - b)
+    const res: number[][] = []
+    const templist: number[] = []
+    const visited: boolean[] = new Array(nums.length).fill(false)
+    backTrack(nums, res, templist, visited)
+    return res
+};
+
+function backTrack(nums, res, templist, visited) {
+    if (templist.length === nums.length) {
+        res.push([].concat(templist))
+        return
+    }
+    for (let i = 0; i < nums.length; i++) {
+        if (visited[i]) {
+            continue
+        }
+        if (i > 0 && nums[i] === nums[i - 1] && !visited[i - 1]) {
+            continue
+        }
+        templist.push(nums[i])
+        visited[i] = true
+        backTrack(nums, res, templist, visited)
+        visited[i] = false
+        templist.pop(nums[i])
+    }
+}
+```
+
+## 练习
+
+-  [subsets](https://leetcode-cn.com/problems/subsets/)
+-  [subsets-ii](https://leetcode-cn.com/problems/subsets-ii/)
+-  [permutations](https://leetcode-cn.com/problems/permutations/)
+-  [permutations-ii](https://leetcode-cn.com/problems/permutations-ii/)
+
+挑战题目
+
+-  [combination-sum](https://leetcode-cn.com/problems/combination-sum/)
+-  [letter-combinations-of-a-phone-number](https://leetcode-cn.com/problems/letter-combinations-of-a-phone-number/)
+-  [palindrome-partitioning](https://leetcode-cn.com/problems/palindrome-partitioning/)
+-  [restore-ip-addresses](https://leetcode-cn.com/problems/restore-ip-addresses/)
+-  [permutations](https://leetcode-cn.com/problems/permutations/)
+