Added maxSubstring problem

MaxSubStringForBinaryString.py

@@ -0,0 +1,49 @@
+
+all_examples = ["1100011","110111000","1000011", "101011"]
+
+def maxSubArray(binaryString):
+    if not binaryString:
+        return []
+
+    maxCount = 0
+    count = 0
+    startIndex = -1
+    length = 0
+    maxLength = 0
+    ans= []
+    for i, n in enumerate(binaryString):
+        if n == '1':
+            count += 1
+        else:
+            count -= 1
+
+        length += 1
+
+        if startIndex == -1:
+            # starting the index again after resetting it
+            startIndex = i
+
+        if count > maxCount:
+            # highest priority of maxCount
+            maxCount = count
+            maxLength = length
+            ans = [binaryString[startIndex:i+1]]
+        elif count == maxCount and length > maxLength:
+            # if count matched, select the one with max length
+            ans = [binaryString[startIndex:i+1]]
+            maxLength = length
+        elif count == maxCount and length == maxLength:
+            # if count and length matches, select both
+            ans.append(binaryString[startIndex:i+1])
+
+        if count < 0:
+            # resetting the count, length and startIndex when count goes negative
+            count = 0
+            length = 0
+            startIndex = -1
+
+    return ans
+
+for s in all_examples:
+    x = maxSubArray(s)
+    print(s, x)