java实现贪心算法-背包问题

//背包问题(贪心算法)
public class GreedyPackage {

    private int MAX_WEIGHT = 150;
    private int[] weights = new int[]{35,30,60,50,40,10,25};
    private int[] values = new int[]{10,40,30,50,35,40,30};

    private void packageGreedy(int capacity,int[] weights,int[] values){
            int n = weights.length;
            double[] r = new double[n]; //性价比数组
            int[] index = new int[n];   //按性价比排序物品的下标
            for(int i = 0;i < n;i++){
                r[i] = (double) values[i] / weights[i];
                index[i] = i;//默认排序
        }

        double temp = 0;    //对性价比进行排序
        for(int i = 0;i < n - 1;i++){
            for(int j = i + 1;j < n;j++){
                if(r[i] < r[j]){
                    temp = r[i];
                    r[i] = r[j];
                    r[j] = temp;
                    int x = index[i];
                    index[i] = index[j];
                    index[j] = x;
                }
            }
        }

        //将排序好的重量和价值分别存到数组中
        int[] w1 = new int[n];
        int[] value1 = new int[n];

        for(int i = 0;i < n;i++){
            w1[i] = weights[index[i]];
            value1[i] = values[index[i]];

        }
        int[] x = new int[n];
        int maxValue = 0;
        for(int i = 0;i < n;i++){
            if(w1[i] <= capacity){   //表明还可以装得下
                x[i] = 1;   //表示该物品被装了
                capacity = capacity - w1[i];
                maxValue += value1[i];
            }
        }
        System.out.println("总共放下的物品数量:" + Arrays.toString(x));
        System.out.println("最大价值为:" + maxValue);
    }


    public static void main(String[] args){
        GreedyPackage g = new GreedyPackage();
        g.packageGreedy(g.MAX_WEIGHT,g.weights,g.values);
    }
}