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
Go 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
func dicePairsScore(dice []int) int {
}Worked examples
| Call | Result |
|---|---|
dicePairsScore([]int{2, 3, 2, 5, 3}) | 5 |
dicePairsScore([]int{6, 6, 6}) | 18 |
dicePairsScore([]int{1, 2, 3}) | 0 |
dicePairsScore([]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 Go
func dicePairsScore(dice []int) int {
freq := map[int]int{}
for _, d := range dice {
freq[d]++
}
sum := 0
for v, k := range freq {
if k >= 2 {
sum += v * k * (k - 1) / 2
}
}
return sum
}