Zigzag Conversion · Interview Problem

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Leetcode

zigzag-conversion

Medium

Strings

Simulation

Zigzag Conversion

Convert a given string into a zigzag pattern on a given number of rows and then read line by line.

Acceptance 100%

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Problem Statement

Core description from the backend problem record.

Description

Given a string s and an integer numRows, arrange the characters of s in a zigzag pattern on numRows rows. Then read the characters row by row to form a new string. The pattern is formed by writing characters diagonally and vertically in a zigzag shape.

For example, the string "PAYPALISHIRING" with numRows = 3 will be written as: P A H N A P L S I I G Y I R

Reading line by line gives "PAHNAPLSIIGYIR" as output.

Implement a function to perform this conversion.

Input Format

A string s representing the string to be converted.
An integer numRows representing the number of rows in zigzag pattern.

Output Format

Return a string which is formed by concatenating characters line by line from the zigzag pattern.

Constraints

1 <= s.length <= 1000
s consists of English letters (lower-case and upper-case), ',' and '.'
1 <= numRows <= 1000

Examples

Sample cases returned by the problem API.

Example 1

Input

s = "PAYPALISHIRING", numRows = 3

Output

"PAHNAPLSIIGYIR"

Explanation

The zigzag pattern is: P A H N A P L S I I G Y I R Concatenating rows gives the output.

Example 2