leetcode 46 全排列-元素交换法

Author: maxleisun

.editorconfig

@@ -1,2 +1,3 @@
 .vscode
-node_modules
+.DS_Store
+node_modules

.gitignore

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+/**
+ * 全排列问题
+ */
+
+/**
+ * 元素交换法
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+exports.permuteByElementReplacement = function (nums) {
+  if (!nums?.length) return nums;
+
+  const result = [];
+
+  function each(pre, res) {
+    if (res.length <= 1) {
+      result.push(pre.concat(res));
+      return;
+    }
+
+    for (let i = 0; i < res.length; i++) {
+      const newRes = [...res];
+      newRes.splice(i, 1, newRes[0]);
+      each(pre.concat(res[i]), newRes.slice(1));
+    }
+  }
+
+  each([], nums);
+
+  return result;
+};

1-99/46.permutation.js

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+const { permuteByElementReplacement } = require("./46.permutation");
+
+function runTest(method) {
+  describe(`46. ${method.name} test`, () => {
+    test("common case 1", () => {
+      expect(method([1, 2, 3])).toHaveLength(6);
+    });
+    test("common case 2", () => {
+      expect(method([1, 2, 3, 4])).toHaveLength(24);
+    });
+  });
+}
+
+runTest(permuteByElementReplacement);