Cipher Cascade

Easy

string caesar-cipher encryption modular-arithmetic

Problem Description

Encrypt a string using a dynamic Caesar cipher where each character is shifted by its position index (0-based). For example, character at index i is shifted by i positions in the alphabet. Handle wraparound and preserve case.

Input Format

A single string containing only English letters (uppercase and lowercase).

Output Format

The encrypted string with each character shifted by its index position.

Constraints

• 1 ≤ string length ≤ 1000

• String contains only a-z and A-Z

• Preserve original case (upper/lower)

• Use modulo 26 for alphabet wraparound

• Index starts from 0

Sample Input/Output

Input:

abc

Output:

ace

Explanation

Index 0: 'a' + 0 = 'a'. Index 1: 'b' + 1 = 'c'. Index 2: 'c' + 2 = 'e'. Result: "ace".

Solution Hints

65
Points

1500ms
Time Limit

128MB
Memory Limit

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