add 44-Permutations

javascript/46-Permutations.js

@@ -0,0 +1,25 @@
+function permute(nums) {
+  const res = [];
+
+  if (nums.length === 1) {
+    return [nums.slice()];
+  }
+
+  for (const i of nums) {
+    let n = nums.shift();
+
+    let perms = permute(nums);
+
+    for (const perm of perms) {
+      perm.push(n);
+    }
+
+    perms.forEach((perm) => {
+      res.push(perm);
+    });
+
+    nums.push(n);
+  }
+
+  return res;
+}