Merge pull request #907 from rohitdbabar/rohitdbabar-patch-2

Added Solution for LeetCode Problem No. 76

Author: spandey1296

LeetCode/76. Minimum Window Substring/Solution.java

@@ -0,0 +1,53 @@
+// https://leetcode.com/problems/minimum-window-substring/
+
+class Solution {
+    public String minWindow(String s, String t) 
+    {
+        if(s.length() == 0 || t.length() == 0)
+            return "";
+        HashMap<Character,Integer> map = new HashMap<>();
+        int n = s.length(),m=t.length();
+        
+        for(int i=0; i<m;i++)
+            map.put(t.charAt(i) , map.getOrDefault(t.charAt(i), 0)+1);
+			
+        int count = map.size();
+        int start =0,end =0,min =Integer.MAX_VALUE;
+        String substring = "";
+        
+        while(end < n)
+        {
+            char ch = s.charAt(end);
+            if(map.containsKey(ch))
+            {
+                map.put(ch , map.get(ch) -1);
+                if(map.get(ch) == 0)
+                    count--;
+            }
+            if(count > 0)
+                end++;
+				
+            else if(count == 0)
+            {
+                while(count == 0)
+                {
+                    if(end-start +1 < min)
+                    {
+                        min = end-start+1;
+                        substring = s.substring(start,end+1);
+                    }
+                    char temp = s.charAt(start);
+                    if(map.containsKey(temp))
+                    {
+                        map.put(temp , map.get(temp)+1);
+                        if(map.get(temp) == 1)
+                           count++;
+                    }
+                    start++;
+                }
+                end++;
+            }
+        }
+        return substring;     
+    }
+}