43 lines
1.6 KiB
Python
43 lines
1.6 KiB
Python
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from collections import Counter
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class Solution:
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def minWindow(self, s: str, t: str) -> str:
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tcounts = Counter(t)
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# If chars of t is not included in the entire
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# s string, then we can just return right away
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if not tcounts <= Counter(s):
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return ""
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tlen = len(t)
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min_window = ""
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for start in range(len(s)):
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end = start + tlen - 1
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# We can all the substrings starting from `start` which is every
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# letter of s
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while end < len(s):
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curr_window = s[start:end + 1]
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curr_window_counts = Counter(curr_window)
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# <= is overloaded for Counters to mean inclusion
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#
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# i.e, counter_a -is-included-in- counter_b
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#
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if tcounts <= curr_window_counts:
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# If no min_window has been computed yet or if current
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# window is shorter, then we assign that as the new
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# min_window
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if min_window == "" or len(curr_window) < len(min_window):
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min_window = curr_window
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# Since at this point, if we keep iterating in the inner loop,
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# we'll only get longer substrings so we just break and proceed
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# to find the substrings starting from the next letter (start + 1)
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break
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end += 1
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return min_window
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