常见查找算法java程序

import java.util.Scanner;

public class Ch1_1 {
    public static void main(String[] args) {

        int[] array = {1,2,3,6,9,10,13,16,45,56};
        Scanner scn = new Scanner(System.in);
        while (scn.hasNext()) {
            int number = scn.nextInt();

            // 顺序查找
            System.out.println("lineSearch index:"+lineSearch(array, number));

            // 二分查找
            System.out.println("lineSearch index:"+binarySearch(array, number));
        }
    }

    // 顺序查找法, 逐个查找, 时间复杂度n
    public static int lineSearch(int[] array, int number) {
        int index = -1;
        for (int i=0;i<array.length;i++) {
            if (array[i] == number) {
                index = i;
                break;
            }
        }
        return index;
    }

    // 二分查找法, 也称折半查找, 限定为有序数列, 时间复杂度O（log2n）
    public static int binarySearch(int[] array, int number) {
        int start = 0;
        int end = array.length-1;
        int mid = end / 2;
        int index = -1;

        while (start <= end) {
            if (array[mid] == number) {
                index = mid;
                break;
            } else if (array[mid] > number) {
                end = mid -1;
                mid = (start + end)/2;
            } else {
                start = mid +1;
                mid = (start + end)/2;
            }
        }
        return index;
    }
}

参考文献：
[1] Data Structure & Algorithm七大查找算法 - Poll的笔记 - 博客园