Data Stream LeetCode Problems: 21 Python Solutions

Data Stream problems by difficulty

Problems with a complete Python solution are listed first, then by ascending problem number.

Easy (6)

Easy problems
No.	Problem	Topics
0703	Kth Largest Element in a Stream	Tree, Design, Binary Search Tree +3
0933	Number of Recent Calls	Design, Queue, Data Stream
1656	Design an Ordered Stream	Design, Array, Hash Table +1
0170	Two Sum III - Data structure designPremium	Design, Array, Hash Table +2
0346	Moving Average from Data StreamPremium	Design, Queue, Array +1
0359	Logger Rate LimiterPremium	Design, Hash Table, Data Stream

Medium (9)

Medium problems
No.	Problem	Topics
0901	Online Stock Span	Stack, Design, Data Stream +1
1352	Product of the Last K Numbers	Design, Array, Math +2
1472	Design Browser History	Stack, Design, Array +3
1670	Design Front Middle Back Queue	Design, Queue, Array +2
2034	Stock Price Fluctuation	Design, Hash Table, Data Stream +2
2526	Find Consecutive Integers from a Data Stream	Design, Queue, Hash Table +2
0362	Design Hit CounterPremium	Design, Queue, Array +2
1429	First Unique NumberPremium	Design, Queue, Array +2
1500	Design a File Sharing SystemPremium	Design, Hash Table, Data Stream +2

Hard (6)

Hard problems
No.	Problem	Topics
0295	Find Median from Data Stream	Design, Two Pointers, Data Stream +2
0352	Data Stream as Disjoint Intervals	Union Find, Design, Hash Table +3
1032	Stream of Characters	Design, Trie, Array +2
1825	Finding MK Average	Design, Queue, Data Stream +2
2102	Sequentially Ordinal Rank Tracker	Design, Data Stream, Ordered Set +1
0642	Design Search Autocomplete SystemPremium	Depth-First Search, Design, Trie +4

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python

Please analyze this context and help me answer the question or solve the problem.

Technical interview · 45 minsolution.pyShared editor · Python 3Longest substring without repeatsMediumGiven a string s, return the length of the longest contiguous substring in which every character is unique.s = "abcabcbb"
→ 31def length_of_longest_substring(s: str) -> int:2 last_seen = {}3 left = best = 04 for right, ch in enumerate(s):5 if ch in last_seen and last_seen[ch] >= left:

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

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GPT-6.1 Terra

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python

Please analyze this context and help me answer the question or solve the problem.

Technical interview · 45 minsolution.pyShared editor · Python 3Longest substring without repeatsMediumGiven a string s, return the length of the longest contiguous substring in which every character is unique.s = "abcabcbb"
→ 31def length_of_longest_substring(s: str) -> int:2 last_seen = {}3 left = best = 04 for right, ch in enumerate(s):5 if ch in last_seen and last_seen[ch] >= left:

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

Type your message...

GPT-6.1 TerraClear chat

QuitEscHide+QCapture+PCrop+OSubmit+EnterPress to get answerLeft/Right+Up/Down+

90%Subscription

python

Please analyze this context and help me answer the question or solve the problem.

Technical interview · 45 minsolution.pyShared editor · Python 3Longest substring without repeatsMediumGiven a string s, return the length of the longest contiguous substring in which every character is unique.s = "abcabcbb"
→ 31def length_of_longest_substring(s: str) -> int:2 last_seen = {}3 left = best = 04 for right, ch in enumerate(s):5 if ch in last_seen and last_seen[ch] >= left:

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

Type your message...

GPT-6.1 TerraClear chat

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QuitEscHide+QCapture+PCrop+OSubmit+EnterPress to get answerLeft/Right+Up/Down+

Data Stream LeetCode Problems: All 21,
With Python Solutions

Data Stream problems by difficulty

Easy (6)

Medium (9)

Hard (6)

When the Data Stream problem arrives live.

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Approach

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Data Stream problems by difficulty

Easy (6)6

Medium (9)9

Hard (6)6

When the Data Stream problem arrives live.

Approach

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Keep exploring

Easy (6)

Medium (9)

Hard (6)