字符串的朴素模式匹配算法

字符串的朴素模式匹配算法

 1 package com.berry.algorithm.string;
 2 
 3 /**
 4  * Created by berry-h on 17-1-16.
 5  */
 6 public class NativeAlgorithm {
 7 
 8     /**
 9      * 字符串的朴素模式匹配算法
10      * @param mStr
11      * @param sStr
12      * @return
13      */
14     public Integer getStartIndex(String mStr, String sStr){
15         if(mStr == null || sStr ==null){
16             return null;
17         }
18 
19         char[] m = mStr.toCharArray();
20         char[] s = sStr.toCharArray();
21         int mLength = mStr.length();
22         int sLength = sStr.length();
23 
24         int i = 0;
25         int j = 0;
26 
27         while(i < mLength && j < sLength){
28 
29             if(m[i] == s[j]){
30                 i++;
31                 j++;
32             }else{
33                 i = i - j + 1;
34                 j = 0;
35             }
36 
37         }
38 
39         if(j >= sLength){
40             return i - sLength;
41         }else{
42             return null;
43         }
44     }
45 
46 }