数组中重复的数字

• https://leetcode.cn/problems/shu-zu-zhong-zhong-fu-de-shu-zi-lcof/submissions/

func findRepeatNumber(nums []int) int {
    bitMap := make([]uint64, len(nums)/64+1)

    var bit uint64
    var slot int
    for _,num := range nums {
        slot = num / 64
        bit = uint64(1)<<(num&63)
        if bitMap[slot] & bit != bit {
            bitMap[slot]  |= bit
        } else {
            return num
        }
    }
    return 0

}