54 lines
1.9 KiB
C#
54 lines
1.9 KiB
C#
/**
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* File: subset_sum_i_naive.cs
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* Created Time: 2023-06-25
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* Author: hpstory (hpstory1024@163.com)
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*/
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namespace hello_algo.chapter_backtracking;
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public class subset_sum_i_naive {
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/* 回溯演算法：子集和 I */
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void Backtrack(List<int> state, int target, int total, int[] choices, List<List<int>> res) {
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// 子集和等於 target 時，記錄解
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if (total == target) {
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res.Add(new List<int>(state));
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return;
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}
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// 走訪所有選擇
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for (int i = 0; i < choices.Length; i++) {
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// 剪枝：若子集和超過 target ，則跳過該選擇
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if (total + choices[i] > target) {
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continue;
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}
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// 嘗試：做出選擇，更新元素和 total
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state.Add(choices[i]);
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// 進行下一輪選擇
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Backtrack(state, target, total + choices[i], choices, res);
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// 回退：撤銷選擇，恢復到之前的狀態
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state.RemoveAt(state.Count - 1);
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}
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}
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/* 求解子集和 I（包含重複子集） */
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List<List<int>> SubsetSumINaive(int[] nums, int target) {
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List<int> state = []; // 狀態（子集）
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int total = 0; // 子集和
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List<List<int>> res = []; // 結果串列（子集串列）
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Backtrack(state, target, total, nums, res);
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return res;
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}
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[Test]
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public void Test() {
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int[] nums = [3, 4, 5];
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int target = 9;
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List<List<int>> res = SubsetSumINaive(nums, target);
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Console.WriteLine("輸入陣列 nums = " + string.Join(", ", nums) + ", target = " + target);
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Console.WriteLine("所有和等於 " + target + " 的子集 res = ");
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foreach (var subset in res) {
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PrintUtil.PrintList(subset);
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}
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Console.WriteLine("請注意，該方法輸出的結果包含重複集合");
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}
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}
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