Count how many different values appear in a list.
Input
Line 1: an integer n.
Line 2: n integers.
Output
The number of distinct values.
Count Distinct Values
Mediumarrayshashing
Examples
Example 1
- Input
5 1 2 2 3 3
- Output
3
Distinct values are 1, 2, 3 — three of them.
Example 2
- Input
4 7 7 7 7
- Output
1
Only one distinct value.
Example 3
- Input
3 1 2 3
- Output
3
All different.
Constraints
- 1 <= n <= 10^5
- -10^9 <= each number <= 10^9
Hints
Reveal hint 1
A set keeps only one copy of each value.
Reveal hint 2
Insert every number into a set and report its size.
Reference solution (spoiler — try it yourself first)
Approach
Insert all values into a set; the answer is the set size.
import sys
d = list(map(int, sys.stdin.read().split()))
n = d[0]
print(len(set(d[1:1 + n])))
Bring us the problem, not a perfect specification
Tell us what needs to change, who it affects and any important deadline. We will review the context and reply with useful next questions.
- 01Share contextDescribe the workflow, constraint or risk.
- 02Clarify togetherWe identify missing facts and useful options.
- 03Choose a startAgree a focused assessment or delivery step.