Merge pull request neetcode-gh#1928 from saip7795/sp/min-window-subst…

…ring

Create: 0076-min-window-substring.rb

ruby/0076-min-window-substring.rb

@@ -0,0 +1,41 @@
+
+def min_window(s, t)
+
+ return "" if t == ""
+ count_t = Hash.new(0)
+ window = Hash.new(0)
+
+ t.each_char do |c|
+ count_t[c] +=1
+ end
+
+ have = 0
+ need = count_t.length
+
+ res = [-1,-1]
+ result_length = 9999999999
+ l = 0
+ (0..s.length-1).each do |r|
+ c = s[r]
+ window[c] +=1
+
+ have +=1 if ((count_t.keys.include?(c)) && (window[c] == count_t[c])) 
+ while(have == need)
+ if (r-l+1) < result_length
+ res = [l,r]
+ result_length = (r-l+1)
+
+ end
+ window[s[l]] -=1
+ have -=1 if ((count_t.keys.include?(s[l])) && (window[s[l]] < count_t[s[l]]))
+ l +=1
+ end
+ end
+ l = res[0]
+ r = res[1]
+ if result_length != 9999999999
+ return s[l..r]
+ else
+ return ""
+ end
+end