feat: 全排列 II

递归与回溯/全排列 II-47.js

@@ -0,0 +1,39 @@
+
+let uniqSymbol = 'X'
+
+let permuteUnique = function (nums) {
+  let n = nums.length
+  if (n === 1) {
+    return [nums]
+  }
+  let permuteSet = (nums) => {
+    let n = nums.length
+    if (n === 0) {
+      return new Set()
+    }
+    if (n === 1) {
+      return new Set(nums)
+    }
+
+    let res = new Set()
+    for (let i = 0; i < n; i++) {
+      let use = nums[i]
+      if (use === undefined) {
+        continue
+      }
+      let rest = nums.slice(0, i).concat(nums.slice(i + 1, n))
+      let restPermuteds = permuteSet(rest)
+      restPermuteds.forEach((restPermuted) => {
+        res.add(`${use}${uniqSymbol}${restPermuted}`)
+      })
+    }
+
+    return res
+  }
+
+  let permuted = permuteSet(nums)
+
+  return Array.from(permuted).map((val) => val.split(uniqSymbol).map(Number))
+}
+
+console.log(permuteUnique([-1,2,-1,2,1,-1,2,1]))