Giải bài toán xếp ba lô (bài toán cái túi) với C++

#include <iostream>
using namespace std;
int max(int x, int y) {
   return (x > y) ? x : y;
}
int tromDo(long long m, int a[], int b[], int n) {
   int i, t;
   int k[n + 1][m + 1];
   for (i = 0; i <= n; i++) {
      for (t = 0; t <= m; t++) {
         if (i == 0 || t == 0)
            k[i][t] = 0;
         else if (b[i - 1] <= t)
            k[i][t] = max(a[i - 1] + k[i - 1][t - b[i - 1]], k[i - 1][t]);
         else
        k[i][t] = k[i - 1][t];
      }
   }
   return k[n][m];
}
int main() {
    freopen("DRSEM.INP","r",stdin);
    freopen("DRSEM.OUT","w",stdout);
    int n; long long m;
    cin >> n >> m;
    int a[n], b[n];
    for (int i = 0; i < n; i++) {
      cin >> a[i];
      cin >> b[i];
    }
   cout << tromDo(m, a, b, n);
   return 0;
}

#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

struct Item {
    int weight;
    int value;
};

int knapsack(int n, int m, const vector<Item>& items) {
    vector<vector<int>> dp(n + 1, vector<int>(m + 1, 0));

    for (int i = 1; i <= n; i++) {
        for (int j = 0; j <= m; j++) {
            if (items[i - 1].weight <= j) {
                dp[i][j] = max(dp[i - 1][j], dp[i - 1][j - items[i - 1].weight] + items[i - 1].value);
            }
            else {
                dp[i][j] = dp[i - 1][j];
            }
        }
    }

    return dp[n][m];
}

int main() {
    ifstream inputFile("DRSEM.INP");
    ofstream outputFile("DRSEM.OUT");

    int n, m;
    inputFile >> n >> m;

    vector<Item> items(n);
    for (int i = 0; i < n; i++) {
        inputFile >> items[i].weight >> items[i].value;
    }

    int maxTotalValue = knapsack(n, m, items);

    outputFile << maxTotalValue << endl;

    inputFile.close();
    outputFile.close();

    return 0;
}

#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

struct Item {
    int weight;
    int value;
};

vector<int> selectedItems; // Lưu trữ vật phẩm được chọn
int maxTotalValue; // Giá trị tối đa có thể đạt được

void knapsack(int currentItem, int currentWeight, int totalValue, const vector<Item>& items, int m) {
    if (currentItem == items.size() || currentWeight >= m) {
        if (totalValue > maxTotalValue) {
            maxTotalValue = totalValue;
            selectedItems.clear();
            for (int i = 0; i < currentItem; i++) {
                if (selectedItems[i])
                    selectedItems.push_back(i);
            }
        }
        return;
    }

    if (currentWeight + items[currentItem].weight <= m) {
        selectedItems[currentItem] = 1;
        knapsack(currentItem + 1, currentWeight + items[currentItem].weight, totalValue + items[currentItem].value, items, m);
    }

    selectedItems[currentItem] = 0;
    knapsack(currentItem + 1, currentWeight, totalValue, items, m);
}

int main() {
    ifstream inputFile("DRSEM.INP");
    ofstream outputFile("DRSEM.OUT");

    int n, m;
    inputFile >> n >> m;

    vector<Item> items(n);
    for (int i = 0; i < n; i++) {
        inputFile >> items[i].weight >> items[i].value;
    }

    selectedItems.resize(n);
    maxTotalValue = 0;

    knapsack(0, 0, 0, items, m);

    outputFile << maxTotalValue << endl;

    inputFile.close();
    outputFile.close();

    return 0;
}