Create 47-permutations-ii.js

Author: everthis

47-permutations-ii.js

@@ -0,0 +1,31 @@
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+const permuteUnique = function(nums) {
+  const result = [];
+  if (nums == null || nums.length === 0) {
+    return result;
+  }
+  const map = {};
+  for (let n of nums) {
+    map[n] = map.hasOwnProperty(n) ? map[n] + 1 : 1;
+  }
+  permuteUniqueHelper(map, nums.length, [], 0, result);
+  return result;
+};
+
+function permuteUniqueHelper(m, l, p, i, r) {
+  if (l === i) {
+    r.push(p.slice(0, l));
+    return;
+  }
+  for (let key of Object.keys(m)) {
+    if (m[key] > 0) {
+      m[key] = m[key] - 1;
+      p[i] = key;
+      permuteUniqueHelper(m, l, p, i + 1, r);
+      m[key] = m[key] + 1;
+    }
+  }
+}