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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3.  
  4. // Item struct
  5. typedef struct { int v, w; float r; } Item;
  6.  
  7. // Compare function for qsort (descending ratio)
  8. int compare(const void *a, const void *b) {
  9.     float rA = ((Item *)a)->r;
  10.     float rB = ((Item *)b)->r;
  11.     if (rA < rB) return 1;
  12.     if (rA > rB) return -1;
  13.     return 0;
  14. }
  15.  
  16. // Greedy Rational Knapsack solution
  17. float knapsack(float capacity, Item items[], int n) {
  18.     float totalValue = 0.0;
  19.     int i;
  20.  
  21.     for (i = 0; i < n; i++) {
  22.         items[i].r = (float)items[i].v / items[i].w;
  23.     }
  24.     qsort(items, n, sizeof(Item), compare);
  25.  
  26.     for (i = 0; i < n; i++) {
  27.         if (capacity <= 0) break;
  28.  
  29.         if (items[i].w <= capacity) {
  30.             totalValue += items[i].v;
  31.             capacity -= items[i].w;
  32.         } else {
  33.             totalValue += items[i].v * (capacity / items[i].w);
  34.             capacity = 0;
  35.         }
  36.     }
  37.     return totalValue;
  38. }
  39.  
  40. // Main function for testing
  41. int main() {
  42.     float W = 50.0;
  43.     Item goods[] = {{60, 10, 0}, {100, 20, 0}, {120, 30, 0}};
  44.     int N = 3;
  45.  
  46.     float result = knapsack(W, goods, N);
  47.  
  48.     printf("Nilai Optimal Knapsack (W=%.0f): %.2f\n", W, result); // Output: 240.00
  49.     return 0;
  50. }
Success #stdin #stdout 0s 5324KB
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stdout 
Nilai Optimal Knapsack (W=50): 240.00
https://ideone.com/VvMeiE
language:
C (gcc 8.3)
created:
4 hours ago
visibility:
public

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