[Leetcode] Minimum Window Substring

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演算法思想： http://www.cnblogs.com/lichen782/p/leetcode_minimum_window_substring_3.html

 1 public class Solution { 2     public String minWindow(String S, String T) { 3         int N = S.length(); 4         int M = T.length(); 5         if(N < M) 6             return ""; 7         int[] need=new int[256]; 8         int[] find=new int[256]; 9         for(int i=0;i<M;++i)10             need[T.charAt(i)]++;11         12         int count=0;13         int resStart=-1;14         int resEnd=N;15         16         for(int start=0,end=0;end<N;++end){17             if(need[S.charAt(end)]==0)18                 continue;19             if(find[S.charAt(end)]<need[S.charAt(end)])20                 count++;21             find[S.charAt(end)]++;22             if(count!=M)23                 continue;24             25             for(;start<end;++start){26                 if(need[S.charAt(start)]==0)27                     continue;28                 if(find[S.charAt(start)]<=need[S.charAt(start)])29                     break;30                 find[S.charAt(start)]--;31             }32             if(end-start<resEnd-resStart){33                 resStart=start;34                 resEnd=end;35             }36         }37         return (resStart==-1)?"":S.substring(resStart, resEnd+1);38     }39 }

 

[Leetcode] Minimum Window Substring