luoheng
10/6/2019 - 2:31 PM

repeatedNTimes

func repeatedNTimes(A []int) int {
    c := make(map[int]bool, 10)
    for _, a := range A {
        if _, ok := c[a]; ok {
            return a
        }
        c[a] = true
    }
    return -1
}