算法与数据结构——二分查找法（2）

public class BinarySearch {

    private BinarySearch(){}

    public static <E extends Comparable<E>> int search(E[] arr,E target){
        int l = 0,r = arr.length;
        // 在 data[l,r) 的范围中查找 target,前闭后开
        while(l < r){
            int mid = l + (r - l)/2;
            if(arr[mid].compareTo(target) == 0){
                return mid;
            }
            if(arr[mid].compareTo(target) < 0){
                l = mid + 1;
            }else{
                r = mid;
            }
        }
        return -1;
    }

    // > target 的最小值索引
    public static <E extends Comparable<E>> int minIndex(E[] arr,E target){
        int l = 0,r = arr.length;
        // 在data[l,r]中寻找解
        while(l < r){
            int mid = l + (r - l)/2;
            if(arr[mid].compareTo(target) <= 0){
                l = mid + 1;
            }else{
                r = mid;
            }
        }
        return l;
    }

    public static void main(String[] args) {
//        Integer[] arr = {1,4,5,8,9,10,11,12,14,16,19};
//        int index = BinarySearch.minIndex(arr, 5);
//        System.out.println(index);
        Integer[] arr = {1,1,3,3,5,5};
        for (int i = 0; i <= 6; i++) {
            System.out.print(BinarySearch.minIndex(arr,i) + " ");
        }
        System.out.println();
    }
}