算法的一些小栗子7（贪心算法）

贪心算法

//贪心背包算法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];//性价比排序物品的下标        for (int i = 0; i < n; i++) {            r[i] = (double) values[i] / (double) weights[i];            index[i] = i;        }        double temp = 0;        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;                }            }        }        //排序好的质量和重量分别存到数组        int[] w1 = new int[n];        int[] v1 = new int[n];        for (int i = 0; i < n; i++) {            w1[i] = weights[index[i]];            v1[i] = values[index[i]];        }        int[] x = new int[n];        int maxValue = 0;        for (int i = 0; i < n; i++) {            if (w1[i] <= capacity) {                //还可以装得下                x[i] = 1;//表示该物品已经被装了                maxValue += v1[i];                System.out.println("物品" + w1[i] + "被放进背包");                capacity = capacity - w1[i];            }        }        System.out.println("总共放下的物品数量：" + Arrays.toString(x));        System.out.println("获取的最大价值：" + maxValue);    }    public static void main(String[] args) {        GreedyPackage greedyPackage = new GreedyPackage();        greedyPackage.packageGreedy(greedyPackage.MAX_WEIGHT, greedyPackage.weights, greedyPackage.values);    }}