Return the Most Frequent Integer with a Stable Tie-Breaker
Company: Bytedance
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Technical Screen
# Return the Most Frequent Integer with a Stable Tie-Breaker
Given a nonempty integer array, return the value that appears most often. If several values have the same highest frequency, return the numerically smallest one.
## Function Contract
```python
def most_frequent_smallest(values: list[int]) -> int:
...
```
## Constraints
- `1 <= len(values) <= 200_000`
- `-10**9 <= values[i] <= 10**9`
- Do not mutate the input.
- Return the integer value, not its frequency or index.
## Examples
```text
values = [4, 1, 4, 2, 2]
result = 2
```
Both `2` and `4` occur twice, so the smaller value is returned.
```text
values = [-1, -1, 3]
result = -1
```
Quick Answer: Implement a frequency-based selection over a large integer array: return the most common value, using the numerically smallest value to break ties. Preserve the input and return the value itself rather than its count or position.
Implement most_frequent_smallest(values). Return the most frequent value in the non-empty integer array. When several values tie for the highest frequency, return the numerically smallest one. Do not mutate the input.
Constraints
- 1 <= len(values) <= 200,000
- -10^9 <= values[i] <= 10^9
- Do not mutate values.
Examples
Input: ([1],)
Expected Output: 1
Explanation: Checks unique maxima and numeric tie-breaking, including negatives.
Input: ([4, 1, 4, 2, 2],)
Expected Output: 2
Explanation: Checks unique maxima and numeric tie-breaking, including negatives.
Hints
- Count each value with a hash map.
- Compare candidates first by larger count and then by smaller numeric value.