public class Test_31 {
    // 动态规划解决0-1背包问题
    public int knapsack(int capacity, int[] weights, int[] values, int n) {
        // 创建一个二维数组dp，用于记录状态转移过程
        int[][] dp = new int[n + 1][capacity + 1];

        // 遍历物品
        for (int i = 1; i <= n; i++) {
            // 遍历背包容量
            for (int w = 1; w <= capacity; w++) {
                if (weights[i - 1] > w) {
                    // 当前物品重量大于背包容量，无法放入，取上一个状态的值
                    dp[i][w] = dp[i - 1][w];
                } else {
                    // 否则比较放入当前物品和不放入当前物品两种情况的最大价值
                    dp[i][w] = Math.max(dp[i - 1][w], values[i - 1] + dp[i - 1][w - weights[i - 1]]);
                }
            }
        }

        // 返回背包问题的最优解
        return dp[n][capacity];
    }

    public static void main(String[] args) {
        Test_31 knapsackProblem = new Test_31();
        int capacity = 15;
        int[] weights = {2, 3, 4, 5};
        int[] values = {3, 4, 5, 6};
        int n = weights.length;

        // 计算获得的最大价值
        int maxValue = knapsackProblem.knapsack(capacity, weights, values, n);
        System.out.println("The maximum value that can be obtained is: " + maxValue);
    }
}