diff --git a/budd-common/src/main/java/io/github/ehlxr/algorithm/Permutation.java b/budd-common/src/main/java/io/github/ehlxr/algorithm/Permutation.java new file mode 100644 index 0000000..ef2bf1b --- /dev/null +++ b/budd-common/src/main/java/io/github/ehlxr/algorithm/Permutation.java @@ -0,0 +1,70 @@ +/* + * The MIT License (MIT) + * + * Copyright © 2022 xrv + * + * 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> res = new ArrayList<>(); + + public static void main(String[] args) { + int[] arr = {1, 2, 3}; + for (List r : permute(arr)) { + for (int i : r) { + System.out.print(i + " "); + } + System.out.println(); + } + } + + public static List> permute(int[] nums) { + List track = new ArrayList<>(); + backtrack(nums, track); + return res; + } + + public static void backtrack(int[] nums, List 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); + } + } +} diff --git a/budd-common/src/main/java/io/github/ehlxr/algorithm/dp/KnapSack.java b/budd-common/src/main/java/io/github/ehlxr/algorithm/dp/KnapSack.java index 2014ce6..135d6cf 100644 --- a/budd-common/src/main/java/io/github/ehlxr/algorithm/dp/KnapSack.java +++ b/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) {