Interactive LeetCode Problems: 21 Python Solutions

Interactive problems by difficulty

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

Easy (4)

Easy problems
No.	Problem	Topics
0278	First Bad Version	Binary Search, Interactive
0374	Guess Number Higher or Lower	Binary Search, Interactive
0157	Read N Characters Given Read4Premium	Array, Interactive, Simulation
2728	Count Houses in a Circular StreetPremium	Array, Interactive

Medium (12)

Medium problems
No.	Problem	Topics
1237	Find Positive Integer Solution for a Given Equation	Math, Two Pointers, Binary Search +1
0277	Find the CelebrityPremium	Graph, Two Pointers, Interactive
0702	Search in a Sorted Array of Unknown SizePremium	Array, Binary Search, Interactive
1236	Web CrawlerPremium	Depth-First Search, Breadth-First Search, String +1
1428	Leftmost Column with at Least a OnePremium	Array, Binary Search, Interactive +1
1533	Find the Index of the Large IntegerPremium	Array, Binary Search, Interactive
1538	Guess the Majority in a Hidden ArrayPremium	Array, Math, Interactive
1618	Maximum Font to Fit a Sentence in a ScreenPremium	Array, String, Binary Search +1
1778	Shortest Path in a Hidden GridPremium	Depth-First Search, Breadth-First Search, Array +2
1810	Minimum Path Cost in a Hidden GridPremium	Depth-First Search, Breadth-First Search, Graph +5
2782	Number of Unique CategoriesPremium	Union Find, Counting, Interactive
2936	Number of Equal Numbers BlocksPremium	Array, Binary Search, Interactive

Hard (5)

Hard problems
No.	Problem	Topics
1095	Find in Mountain Array	Array, Binary Search, Interactive
0158	Read N Characters Given read4 II - Call Multiple TimesPremium	Array, Interactive, Simulation
0489	Robot Room CleanerPremium	Backtracking, Interactive
0843	Guess the Word	Array, Math, String +2
1274	Number of Ships in a RectanglePremium	Array, Divide and Conquer, Interactive

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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+

Interactive LeetCode Problems: All 21,
With Python Solutions

Interactive problems by difficulty

Easy (4)

Medium (12)

Hard (5)

When the Interactive problem arrives live.

Approach

Approach

Approach

Keep exploring

Interactive problems by difficulty

Easy (4)4

Medium (12)12

Hard (5)5

When the Interactive problem arrives live.

Approach

Approach

Approach

Keep exploring

Easy (4)

Medium (12)

Hard (5)