65 lines
2.1 KiB
C#
65 lines
2.1 KiB
C#
/**
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* File: unbounded_knapsack.cs
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* Created Time: 2023-07-12
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* Author: hpstory (hpstory1024@163.com)
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*/
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namespace hello_algo.chapter_dynamic_programming;
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public class unbounded_knapsack {
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/* Complete knapsack: Dynamic programming */
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int UnboundedKnapsackDP(int[] wgt, int[] val, int cap) {
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int n = wgt.Length;
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// Initialize dp table
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int[,] dp = new int[n + 1, cap + 1];
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// State transition
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for (int i = 1; i <= n; i++) {
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for (int c = 1; c <= cap; c++) {
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if (wgt[i - 1] > c) {
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// If exceeding the knapsack capacity, do not choose item i
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dp[i, c] = dp[i - 1, c];
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} else {
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// The greater value between not choosing and choosing item i
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dp[i, c] = Math.Max(dp[i - 1, c], dp[i, c - wgt[i - 1]] + val[i - 1]);
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}
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}
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}
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return dp[n, cap];
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}
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/* Complete knapsack: Space-optimized dynamic programming */
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int UnboundedKnapsackDPComp(int[] wgt, int[] val, int cap) {
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int n = wgt.Length;
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// Initialize dp table
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int[] dp = new int[cap + 1];
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// State transition
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for (int i = 1; i <= n; i++) {
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for (int c = 1; c <= cap; c++) {
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if (wgt[i - 1] > c) {
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// If exceeding the knapsack capacity, do not choose item i
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dp[c] = dp[c];
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} else {
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// The greater value between not choosing and choosing item i
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dp[c] = Math.Max(dp[c], dp[c - wgt[i - 1]] + val[i - 1]);
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}
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}
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}
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return dp[cap];
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}
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[Test]
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public void Test() {
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int[] wgt = [1, 2, 3];
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int[] val = [5, 11, 15];
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int cap = 4;
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// Dynamic programming
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int res = UnboundedKnapsackDP(wgt, val, cap);
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Console.WriteLine("The maximum value within the bag capacity is" + res);
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// Space-optimized dynamic programming
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res = UnboundedKnapsackDPComp(wgt, val, cap);
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Console.WriteLine("The maximum value within the bag capacity is" + res);
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}
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}
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