Missing Letter

L2 Easy Strings

Concept

Comparing two letter bags by tallying one and subtracting the other reveals exactly which character is extra.

The string t contains every character of s plus one extra character somewhere. Return that extra character as a single-character string.

Examples

▸ s = "abcd", t = "acbde"

→ "e"

▸ s = "xyz", t = "xzyy"

→ "y"

▸ s = "", t = "a"

→ "a"

Progressive Hints

Hint 1 · Nudge

Compare two bags of letters, and one of them has one extra item.

Hint 2 · Plan

Tally the letters of t. Subtract each letter of s from the tallies, then look for the letter whose tally is still positive. That's the extra one.

Hint 3 · Approach

counts = tally of t's characters. For each c in s: counts[c] = counts[c] - 1. Return the character whose tally is still greater than 0.

Output

// Run your code to see the output here.