在一个有序数组中，找>=某个数最左的位置和<=的最右的位置

public class BSNearLeft {
    public static int nearestIndex(int[] arr, int value) {
        int L = 0;
        int R = arr.length - 1;
        int mid = 0;
        int index = -1;
        while (L <= R) { //等于R是要把所有的数都测试完
            mid = L + ((R - L) >> 1);
            if (arr[mid] >= value) {
                index = mid;    //如果>=value 标记一个对号
                R = mid - 1;
            } else {
                L = mid + 1;
            }
        }
        return index;
    }

    public static void main(String[] args) {
        int[] arr = {0,0,0,1,1,2,2,2,2,2,2,3,3,3,3,3,4,4,4};
        int result = nearestIndex(arr,2);
        System.out.println(result);
    }
}

public class BSNearRight {
    public static int nearestIndex(int[] arr,int value){
        int L = 0;
        int R = arr.length - 1;
        int mid = 0;
        int index = -1;
        while (L <= R) { //等于R是要把所有的数都测试完
            mid = L + ((R - L) >> 1);
            if (arr[mid] <= value) {
                index = mid;    //如果>=value 标记一个对号
                L = mid + 1;
            } else {
                R = mid - 1;
            }
        }
        return index;
    }
    public static void main(String[] args) {
        int[] arr = {0,0,0,1,1,2,2,2,2,2,2,3,3,3,3,3,4,4,4};
        int result = nearestIndex(arr,2);
        System.out.println(result);
    }
}