First Letter Seen Again

Easy

You read a string text of lowercase English letters from left to right, noting each letter as you go. Return the letter you run into for the second time first. In other words, every repeated letter has a position of its second occurrence; return the letter whose second occurrence comes earliest. At least one letter is guaranteed to repeat.

Example 1

text="rocketry" → 'r'

Only r repeats, at positions 0 and 6, so it is the answer.

Example 2

text="banana" → 'a'

The second a is at index 3 and the second n at index 4, so a repeats first.

Example 3

text="zz" → 'z'

Constraints

2 ≤ len(text) ≤ 100
text consists of lowercase English letters
At least one letter appears twice

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Topics

Bit Manipulation Hash Table String Counting

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Input

text="rocketry"

Expected

'r'

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