package com.interview.string;

/**
 * References
 * https://leetcode.com/problems/minimum-window-substring/
 * http://www.geeksforgeeks.org/find-the-smallest-window-in-a-string-containing-all-characters-of-another-string/
 */
import java.util.HashMap;
import java.util.Map;

public class SmallestWindowContaingAllCharacters {

    public String minWindow(String s, String t) {
        Map<Character, Integer> countMap = new HashMap<>();
        for (char ch : t.toCharArray()) {
            Integer val = countMap.get(ch);
            if (val == null) {
                val = 0;
            }
            countMap.put(ch, val + 1);
        }
        int start = 0;
        int currLen = t.length();
        int minWindow = Integer.MAX_VALUE;
        int minStart = 0;
        int i = 0;
        while (i < s.length()) {
            Integer val = countMap.get(s.charAt(i));
            if (val == null) {
                i++;
                continue;
            }
            if (val > 0) {
                currLen--;
            }
            val--;
            countMap.put(s.charAt(i), val);
            while (currLen == 0) {
                if (minWindow > i - start + 1) {
                    minWindow = i - start + 1;
                    minStart = start;
                }
                Integer val1 = countMap.get(s.charAt(start));
                if (val1 != null) {
                    if (val1 == 0) {
                        break;
                    } else {
                        val1++;
                        countMap.put(s.charAt(start), val1);
                    }
                }
                start++;
            }
            i++;
        }

        return minWindow != Integer.MAX_VALUE ? s.substring(minStart, minStart + minWindow) : "";
    }

    public static void main(String args[]) {

        String str = "Tsuaosyogrlmnsluuorjkoruost";
        String subString = "soor";
        SmallestWindowContaingAllCharacters swcac = new SmallestWindowContaingAllCharacters();
        String result = swcac.minWindow(str, subString);
        System.out.println(result);
    }

}