查找算法

1、线性查找

2、二分查找

PS：后续或有更新

 1 public class Search {
 2 
 3     /**
 4      *线性查找方法
 5      **/
 6     public static int linearSearch(int[] obj, int value) {
 7         int i;
 8         int result;
 9         for (i = 0; i < obj.length; ++i) {
10             if (value == obj[i]) {
11                 break;
12             }
13         }
14         if (i == obj.length) {
15             result = -1;
16         } else {
17             result = i;
18         }
19         return result;
20     }
21 
22     /**
23      *二分查找方法
24      **/
25     public static int binarySearch(int[] obj, int value) {
26         int middle = 0;
27         int low = 0;
28         int top = obj.length + 1;
29         //System.out.println(low +" " + middle +" " + top);
30 
31         while (true) {
32             middle = (low + top) / 2;
33             if (value == obj[middle]) {
34                 return middle;
35             } else if (low > top) {
36                 return -1;
37             } else {
38                 if (value < obj[middle]) {
39                     top = middle - 1;
40                 } else {
41                     low = middle + 1;
42                 }
43             }
44             //System.out.println(low +" " + middle +" " + top);
45         }
46     }
47 
48     /**
49      *显示数据方法
50      **/
51     public static void display(int[] obj) {
52         System.out.print("[");
53         for (int i = 0; i < obj.length; ++i) {
54             System.out.print(obj[i]);
55             if (i != obj.length - 1) {
56                 System.out.print(",");
57             }
58         }
59         System.out.println("]");
60 
61     }
62     public static void main(String[] args) {
63         int[] nums = new int[]{10, 2, 22, 4, 59, 99};
64         Search.display(nums);
65 
66         System.out.println(Search.linearSearch(nums, 2));
67 
68         System.out.println(Search.binarySearch(nums, 10));
69         System.out.println(Search.binarySearch(nums, 2));
70         System.out.println(Search.binarySearch(nums, 22));
71         System.out.println(Search.binarySearch(nums, 4));
72         System.out.println(Search.binarySearch(nums, 59));
73         System.out.println(Search.binarySearch(nums, 99));
74 
75 
76     }
77 }

 

posted @ 2017-07-29 18:17  valuestack  阅读(96)  评论(0)    收藏  举报