func birthday(s []int32, d int32, m int32) int32 {
    prefixSums := make([]int32, len(s)+1)
    for i, n := range s {
        prefixSums[i+1] = prefixSums[i] + n
    }
    
    var countOfSegments int32
    for i := m; i < int32(len(prefixSums)); i++ {
        if prefixSums[i] - prefixSums[i-m] == d {
            countOfSegments++
        }
    }
    return countOfSegments
}