algorithms/minimumWindow.java at master · kjayashr/algorithms · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
/*
Input: S = "ADOBECODEBANC", T = "ABC"
Output: "BANC"
*/

class Solution {
    public String minWindow(String s, String t) {
        if(t.length()> s.length()) return "";
        String res = "";

        HashMap<Character,Integer> map = new HashMap<Character,Integer>();
        for(char c: t.toCharArray())
        {
            map.put(c,map.getOrDefault(c,0)+1);
        }
        int counter = map.size();
        int begin = 0; int end = 0;int head =0;
        int len = Integer.MAX_VALUE;

        while(end < s.length()){
            char c = s.charAt(end);
            if( map.containsKey(c) ){
                map.put(c, map.get(c)-1);
                if(map.get(c) == 0) counter--;
            }
            end++;


            while(counter == 0)
            {
                char tempc = s.charAt(begin);
                if(map.containsKey(tempc))
                {
                    map.put(tempc,map.get(tempc)+1);

                  if(map.get(tempc) > 0)
                   {
                        counter++;
                    }
                }
                if(end-begin < len)
                {
                    len = end-begin;
                    head = begin;
                    res = s.substring(head,end);
                }
             begin++;
            }


        }
         if(len == Integer.MAX_VALUE) return "";
        return res;


    }
}
//madbahudeno