Coursera OA,面经整理

 1 private static String approximateMatch(String pre, String middle, String post) {
 2         int preSize = pre.length();
 3         int middleSize = middle.length();
 4         int postSize = post.length();
 5         int preVal; //indicate the max length in pre
 6         int postVal;//indicate the max length in post
 7         int preIndex = 0; //the start index of maxPre string
 8         int postIndex = 0;// the end index of max post string
 9         
10         //initialization
11         int GobalMax = 0;
12         int LocalMax = 0;
13         int start = 0;
14         
15         //get preVal        
16         for (;start  < preSize ; start++) {
17             LocalMax = 0;
18             while ( start + LocalMax < preSize &&  LocalMax  < middleSize && middle.charAt(LocalMax) == pre.charAt(start + LocalMax)) {                
19                 LocalMax++;
20             }
21             if (LocalMax > GobalMax) {
22                 GobalMax = LocalMax;
23                 preIndex = start;
24             }
25 
26             if (GobalMax > preSize - start) {
27                 break;
28             }
29         }
30         preVal = GobalMax;        
31     
32         //initialization for right part
33         int end =  postSize - 1;
34         GobalMax = 0;
35         int midEnd = middleSize - 1;
36         //get postVal
37         for (; end >= 0; end--) {
38             LocalMax = 0;
39             
40             while (end - LocalMax >= 0 && LocalMax < middleSize 
41                     &&  middle.charAt(midEnd - LocalMax) == post.charAt(end - LocalMax)) {
42                 LocalMax++;
43             }
44             if (LocalMax > GobalMax) {
45                 GobalMax = LocalMax;
46                 postIndex = end + 1;
47             }
48             
49             if (GobalMax > end) {
50                 break;
51             }
52         }
53         postVal = GobalMax;
54         
55         //return result string
56         if (preVal + postVal >= middleSize) {
57             return middle;
58         } else {
59             return pre.substring(preIndex, preVal + preIndex) + post.substring(postIndex - postVal, postIndex);
60         }
61     }