Score dice pairs
A dice game awards points from matching pairs. For each face value that appears more than once, every pair of matching dice contributes the face value to the total score.
- Count how many times each face value appears.
- A face appearing k times forms k*(k-1)/2 pairs.
- Each pair scores the face value.
- If no value repeats, the score is zero.
DicePairsScore(dice: list<int>) → int
C# needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
public int DicePairsScore(List<int> dice) {
}Worked examples
| Call | Result |
|---|---|
DicePairsScore(new List<int> { 2, 3, 2, 5, 3 }) | 5 |
DicePairsScore(new List<int> { 6, 6, 6 }) | 18 |
DicePairsScore(new List<int> { 1, 2, 3 }) | 0 |
DicePairsScore(new List<int> { 4, 4, 4, 4 }) | 24 |
Hint
Count frequencies, then for each face with two or more occurrences add value * count * (count - 1) / 2.
Reference solution in C#
public int DicePairsScore(List<int> dice) {
var freq = new Dictionary<int, int>();
foreach (int d in dice) {
if (freq.ContainsKey(d)) freq[d]++;
else freq[d] = 1;
}
int sum = 0;
foreach (var kv in freq) {
int k = kv.Value;
if (k >= 2) sum += kv.Key * k * (k - 1) / 2;
}
return sum;
}