Merge branch 'master' of https://github.com/wistrasy/Python

Author: wistrasy

strings/min_window_substring.py

@@ -26,62 +26,60 @@ def min_window(search_str: str, target_letters: str) -> str:
     target_count = len(target_letters)
     search_len = len(search_str)
 
-
-    #Return if not possible due to string lengths.
-    if (search_len < target_count):
+    # Return if not possible due to string lengths.
+    if search_len < target_count:
         return ""
 
-    #Build dictionary with counts for each letter in target_letters
+    # Build dictionary with counts for each letter in target_letters
     char_dict = {}
     for ch in target_letters:
         if ch not in char_dict:
             char_dict[ch] = 1
         else:
             char_dict[ch] += 1
 
-    #Initialize window
+    # Initialize window
     window_start = 0
     window_end = 0
 
     exists = False
     min_window_len = search_len + 1
 
-    #Start sliding window algorithm
-    while(window_end < search_len):
-
-        #Slide window end right until all search characters are contained
-        while(target_count > 0 and window_end < search_len):
+    # Start sliding window algorithm
+    while window_end < search_len:
+        # Slide window end right until all search characters are contained
+        while target_count > 0 and window_end < search_len:
             cur = search_str[window_end]
             if cur in char_dict:
                 char_dict[cur] -= 1
-                if (char_dict[cur] >= 0):
+                if char_dict[cur] >= 0:
                     target_count -= 1
             window_end += 1
         temp = window_end - window_start
 
-        #Check if window is the smallest found so far
-        if (target_count == 0 and temp < min_window_len):
-            min_window = [window_start,window_end]
+        # Check if window is the smallest found so far
+        if target_count == 0 and temp < min_window_len:
+            min_window = [window_start, window_end]
             exists = True
             min_window_len = temp
 
-        #Slide window start right until a search character exits the window
-        while(target_count == 0 and window_start < window_end):
+        # Slide window start right until a search character exits the window
+        while target_count == 0 and window_start < window_end:
             cur = search_str[window_start]
             window_start += 1
             if cur in char_dict:
                 char_dict[cur] += 1
-                if (char_dict[cur] > 0):
+                if char_dict[cur] > 0:
                     break
         temp = window_end - window_start + 1
 
-        #Check if window is the smallest found so far
-        if (temp < min_window_len and target_count == 0):
-            min_window = [window_start-1,window_end]
+        # Check if window is the smallest found so far
+        if temp < min_window_len and target_count == 0:
+            min_window = [window_start - 1, window_end]
             min_window_len = temp
         target_count = 1
 
-    if (exists):
-        return search_str[min_window[0]:min_window[1]]
+    if exists:
+        return search_str[min_window[0] : min_window[1]]
     else:
         return ""