permutaion

budd-common/src/main/java/io/github/ehlxr/algorithm/Permutation.java

@@ -0,0 +1,70 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright © 2022 xrv <xrv@live.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package io.github.ehlxr.algorithm;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 全排列
+ *
+ * @author ehlxr
+ * @since 2022-04-20 16:42.
+ */
+public class Permutation {
+    static List<List<Integer>> res = new ArrayList<>();
+
+    public static void main(String[] args) {
+        int[] arr = {1, 2, 3};
+        for (List<Integer> r : permute(arr)) {
+            for (int i : r) {
+                System.out.print(i + " ");
+            }
+            System.out.println();
+        }
+    }
+
+    public static List<List<Integer>> permute(int[] nums) {
+        List<Integer> track = new ArrayList<>();
+        backtrack(nums, track);
+        return res;
+    }
+
+    public static void backtrack(int[] nums, List<Integer> track) {
+        // 回溯结束条件
+        if (track.size() == nums.length) {
+            res.add(new ArrayList<>(track));
+            return;
+        }
+        for (int num : nums) {
+            if (track.contains(num)) {
+                continue;
+            }
+            track.add(num);
+            backtrack(nums, track);
+            track.remove(track.size() - 1);
+        }
+    }
+}

budd-common/src/main/java/io/github/ehlxr/algorithm/dp/KnapSack.java

@@ -39,7 +39,7 @@ public class KnapSack {
 
     public static void main(String[] args) {
         System.out.println(knapsack3(new int[]{2, 2, 4, 6, 3}, new int[]{3, 4, 8, 9, 6}, 5, 9));
-        System.out.println(knapsack(new int[]{2, 2, 4, 6, 3}, new int[]{3, 4, 8, 9, 6}, 5, 9));
+        // System.out.println(knapsack(new int[]{2, 2, 4, 6, 3}, new int[]{3, 4, 8, 9, 6}, 5, 9));
     }
 
     /**
@@ -51,17 +51,17 @@ public class KnapSack {
      * @param w      背包可承载重量
      * @return 最大价值
      */
-    public static int knapsack(int[] weight, int[] value, int n, int w) {
-        int[][] dp = new int[][];
-    }
+    // public static int knapsack(int[] weight, int[] value, int n, int w) {
+    //     int[][] dp = new int[][];
+    // }
 
     /**
      * 动态规划方式
      *
      * @param weight 物品重量
      * @param value  物品的价值
-     * @param n     物品个数
-     * @param w     背包可承载重量
+     * @param n      物品个数
+     * @param w      背包可承载重量
      * @return 最大价值
      */
     public static int knapsack3(int[] weight, int[] value, int n, int w) {