How hard is LeetCode 884. Uncommon Words from Two Sentences?

LeetCode 884. Uncommon Words from Two Sentences is rated Easy on LeetCode.

What is the time complexity of LeetCode 884. Uncommon Words from Two Sentences?

The Python solution on this page runs in O(m + n).

What is the space complexity of LeetCode 884. Uncommon Words from Two Sentences?

The Python solution on this page uses O(m + n) auxiliary space.

What topics does LeetCode 884. Uncommon Words from Two Sentences cover?

LeetCode 884. Uncommon Words from Two Sentences is tagged Hash Table, String and Counting on LeetCode.

EasyNo. 0884

Uncommon Words from Two Sentences — LeetCode 884 Python Solution

Pattern: Hash Map
Topics: Hash Table, String, Counting
Reading time: 2 min
Source: leetcode.com

The problem

A sentence is a string of single-space separated words where each word consists only of lowercase letters. A word is uncommon if it appears exactly once in one of the sentences, and does not appear in the other sentence.

Python solution

PythonSolution

class Solution:
    def uncommonFromSentences(self, s1: str, s2: str) -> List[str]:
        cnt = Counter(s1.split()) + Counter(s2.split())
        return [s for s, v in cnt.items() if v == 1]

Complexity

Time: O(m + n)
Space · auxiliary: O(m + n)

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 884. Uncommon Words from Two Sentences is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Hash Table and Counting.

The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.

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0767	Reorganize String	Medium

Frequently asked questions

How hard is LeetCode 884. Uncommon Words from Two Sentences?: LeetCode 884. Uncommon Words from Two Sentences is rated Easy on LeetCode.
What is the time complexity of LeetCode 884. Uncommon Words from Two Sentences?: The Python solution on this page runs in O(m + n).
What is the space complexity of LeetCode 884. Uncommon Words from Two Sentences?: The Python solution on this page uses O(m + n) auxiliary space.
What topics does LeetCode 884. Uncommon Words from Two Sentences cover?: LeetCode 884. Uncommon Words from Two Sentences is tagged Hash Table, String and Counting on LeetCode.

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python

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

Transcript

"Okay, next one. Given a string, return the length of the longest substring that has no repeating characters. Walk me through your approach before you code it."

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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Transcribing...

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python

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

Transcript

"Okay, next one. Given a string, return the length of the longest substring that has no repeating characters. Walk me through your approach before you code it."

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

Transcribing...

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.

Transcript

"Okay, next one. Given a string, return the length of the longest substring that has no repeating characters. Walk me through your approach before you code it."

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

Transcribing...

Primary display

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

The problem

Python solution

Complexity

Pattern: Hash Map

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Frequently asked questions

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Approach

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