LeetCode: Minimum Window Substring

自己写的large没过，用了map，然后用了很多erase, iterator的，懂得一个道理，map这玩意比较慢，尽量少用，在用网上答案的时候没有给数组初始化为0就过不了

 1 class Solution {

 2 public:

 3     string minWindow(string S, string T) {

 4         // Start typing your C/C++ solution below

 5         // DO NOT write int main() function

 6         int tag[256] = {0};

 7         int mark[256] = {0};

 8         int chars, count, head, beg;

 9         chars = count = head = 0;

10         beg = -1;

11         int min_w = INT_MAX;

12         for (int i = 0; i < T.size(); i++) {

13             if (!tag[T[i]]) chars++;

14             tag[T[i]]++;

15         }

16         for (int i = 0; i < S.size(); i++) {

17             if (!tag[S[i]]) continue;

18             mark[S[i]]++;

19             if (mark[S[i]] == tag[S[i]]) count++;

20             if (chars == count) {

21                 while (!tag[S[head]] || mark[S[head]] > tag[S[head]]) {

22                     mark[S[head]]--;

23                     head++;

24                 }

25                 if (i-head < min_w) {

26                     min_w = i-head;

27                     beg = head;

28                 }

29             }

30         }

31         if (beg == -1) return "";

32         else return S.substr(beg, min_w+1);

33     }

34 };

 C#

 1 public class Solution {

 2     public string MinWindow(string s, string t) {

 3         int[] tag = new int[256];

 4         int[] mark = new int[256];

 5         int chars = 0, count = 0, head = 0, beg = -1;

 6         int min_w = Int32.MaxValue;

 7         for (int i = 0; i < t.Length; i++) {

 8             if (tag[t[i]] == 0) chars++;

 9             tag[t[i]]++;

10         }

11         for (int i = 0; i < s.Length; i++) {

12             if (tag[s[i]] == 0) continue;

13             mark[s[i]]++;

14             if (mark[s[i]] == tag[s[i]]) count++;

15             if (chars == count) {

16                 while (tag[s[head]] == 0 || mark[s[head]] > tag[s[head]]) {

17                     mark[s[head]]--;

18                     head++;

19                 }

20                 if (i - head < min_w) {

21                     min_w = i - head;

22                     beg = head;

23                 }

24             }

25         }

26         if (beg == -1) return "";

27         else return s.Substring(beg, min_w + 1);

28     }

29 }

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