Java 复习

斗地主案例 排序每张扑克

 //二分法

public static void main(String[] args) {
        // 二分法
        int[] arr1 = {1, 2, 3, 5, 5, 7, 8, 9};
        ps1(arr1,9);
        // 递归
        ps2(arr1, 6, 0, arr1.length - 1);
    }

    public static void ps1(int[] data, int target) {
        int left = 0;
        int right = data.length - 1;
        while (left <= right) {
            int middle = (left + right) / 2;
            System.out.println(Arrays.toString(Arrays.copyOfRange(data, left, right + 1)));
            if (data[middle] > target) {
                right = middle - 1;
            } else if (data[middle] < target) {
                left = middle + 1;
            } else {
                System.out.println("index:" + middle + "val:" + data[middle]);
                break;
            }
        }

    }

    public static void ps2(int[] data, int target, int left, int right) {
        if (left > right) {
            return;
        }
        int middle = (left + right) / 2;
        if (data[middle] > target) {
            ps2(data, target, left, middle - 1);
        } else if (data[middle] < target) {
            ps2(data, target, middle + 1, right);
        } else {
            System.out.println("index:" + middle + "val:" + data[middle]);
            return;
        }
    }

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