LeetCode-Questions/76.minimum-window-substring.java at main · sai-Ga/LeetCode-Questions · GitHub

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class Solution {
    public String minWindow(String s, String t) {

        if(s.length() == 0 || t.length() == 0 || s.length() < t.length()){
            return "";
        }

        Map<Character, Integer> mapT = new HashMap<>();

        for(int i=0; i< t.length(); i++){
            mapT.put(t.charAt(i), mapT.getOrDefault(t.charAt(i),0) + 1);
        }

        int required = mapT.size();
        int l = 0, r =0;
        int create = 0;
        int [] ans = {-1, 0, 0};
        Map<Character, Integer> subStringMap = new HashMap<>();

        while(r<s.length()){
            char c = s.charAt(r);
            int count = subStringMap.getOrDefault(c,0);
            subStringMap.put(c, count + 1);
            if(mapT.containsKey(c) && subStringMap.get(c).intValue() == mapT.get(c).intValue()){
                create++;
            }
            while(l <= r && required == create){
                c = s.charAt(l);
                if(ans[0] == -1 || ans[0] >= r-l+1){
                    ans[0] = r -l +1;
                    ans[1] = l;
                    ans[2] = r;
                }

                subStringMap.put(c,subStringMap.get(c) - 1);
                if(mapT.containsKey(c) && subStringMap.get(c).intValue() < mapT.get(c).intValue()){
                    create--;
                }
                l++;
            }
            r++;
        }


        if(ans[0] == -1){
            return "";
        }
        else{
            return s.substring(ans[1], ans[2]+1);
        }


    }
}