feat: 子集和组合

Author: sl1673495

递归与回溯/子集-78.js

@@ -0,0 +1,32 @@
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+let subsets = function (nums) {
+  let res = []
+  let n = nums.length
+  if (n === 0) {
+    return res
+  }
+
+  let helper = (start, prev, targetLength) => {
+    if (start > n) {
+      return
+    }
+    if (prev.length === targetLength) {
+      res.push(prev)
+      return
+    }
+
+    for (let i = start; i < n; i++) {
+      let cur = nums[i]
+      helper(i + 1, prev.concat(cur), targetLength)
+    }
+  }
+
+  for (let j = 1; j <= nums.length; j++) {
+    helper(0, [], j)
+  }
+
+  return [[], ...res]
+}

递归与回溯/组合-77.js

@@ -0,0 +1,28 @@
+/**
+ * @param {number} n
+ * @param {number} k
+ * @return {number[][]}
+ */
+let combine = function (n, k) {
+  let ret = []
+
+  let helper = (start, prev) => {
+    let len = prev.length
+    if (len === k) {
+      ret.push(prev)
+      return
+    }
+
+    if (start > n) {
+      return
+    }
+
+    for (let i = start; i <= n; i++) {
+      helper(i + 1, prev.concat(i))
+    }
+  }
+  helper(1, [])
+  return ret
+}
+
+console.log(combine(4, 2))