How hard is LeetCode 2639. Find the Width of Columns of a Grid?

LeetCode 2639. Find the Width of Columns of a Grid is rated Easy on LeetCode.

What is the time complexity of LeetCode 2639. Find the Width of Columns of a Grid?

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

What is the space complexity of LeetCode 2639. Find the Width of Columns of a Grid?

The Python solution on this page uses O(\log M) auxiliary space.

What topics does LeetCode 2639. Find the Width of Columns of a Grid cover?

LeetCode 2639. Find the Width of Columns of a Grid is tagged Array and Matrix on LeetCode.

EasyNo. 2639

Find the Width of Columns of a Grid — LeetCode 2639 Python Solution

Pattern: Matrix and Grid
Topics: Array, Matrix
Reading time: 2 min
Source: leetcode.com

The problem

You are given a 0-indexed m x n integer matrix grid. The width of a column is the maximum length of its integers.

Example

Input: grid = [[1],[22],[333]]
Output: [3]
Explanation: In the 0th column, 333 is of length 3.

Python solution

PythonSolution

class Solution:
    def findColumnWidth(self, grid: List[List[int]]) -> List[int]:
        return [max(len(str(x)) for x in col) for col in zip(*grid)]

Complexity

Time: O(m × n)
Space · auxiliary: O(log M)

Pattern: Matrix and Grid

Treat a 2-D grid as a graph whose neighbours are the four adjacent cells. LeetCode 2639. Find the Width of Columns of a Grid is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Matrix.

The matrix and grid guide has the Python template for the pattern and the 216 LeetCode problems that use it.

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No.	Problem	Difficulty
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0289	Game of Life	Medium
0498	Diagonal Traverse	Medium
0566	Reshape the Matrix	Easy

Frequently asked questions

How hard is LeetCode 2639. Find the Width of Columns of a Grid?: LeetCode 2639. Find the Width of Columns of a Grid is rated Easy on LeetCode.
What is the time complexity of LeetCode 2639. Find the Width of Columns of a Grid?: The Python solution on this page runs in O(m × n).
What is the space complexity of LeetCode 2639. Find the Width of Columns of a Grid?: The Python solution on this page uses O(log M) auxiliary space.
What topics does LeetCode 2639. Find the Width of Columns of a Grid cover?: LeetCode 2639. Find the Width of Columns of a Grid is tagged Array and Matrix 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.

Type your message...

GPT-6.1 Terra

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

Example

Python solution

Complexity

Pattern: Matrix and Grid

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