1 class Solution {
2 public:
3 //reference: http://www.cnblogs.com/remlostime/archive/2012/11/16/2774077.html
4 string minWindow(string S, string T) {
5 int flag[128];
6 memset(flag, 0, sizeof(flag));
7 int lenT = T.length();
8 if (lenT <= 0)
9 return "";
10 int n=0;
11 for (int i = 0; i < lenT; i++){
12 int index = (int)(T.at(i));
13 if (flag[index] == 0)
14 n++;
15 flag[index]++;
16 }
17 int alFlag[128];
18 memset(alFlag, 0, sizeof(alFlag));
19 int numAl = 0;
20 const char * start = S.c_str();
21 const int maxNum = 1000000000;
22 int rltSize = maxNum;
23 const char* startPos = NULL;
24 const char * end = start;
25 while (*end != '\0'){
26 int index = (int)(*end);
27 alFlag[index]++;
28 if (alFlag[index] == flag[index])
29 numAl++;
30 if (numAl == n){
31 while (start <= end){
32 if (rltSize > end - start + 1){
33 rltSize = end - start + 1;
34 startPos = start;
35 }
36 int ind = (int)(*start);
37 alFlag[ind]--;
38 if (flag[ind] !=0 && alFlag[ind] == flag[ind]-1)
39 numAl--;
40 if (numAl < n){
41 start++;
42 break;
43 }
44 start++;
45 }
46 }
47 end++;
48 }
49 if (startPos == NULL)
50 return "";
51 string rlt="";
52 while (rltSize-- > 0)
53 rlt += *(startPos++);
54 return rlt;
55 }
56 };
