376摆动序列.md

func wiggleMaxLength(nums []int) int {
    var res, curDiff, preDiff int
    res = 1
    if len(nums) == 1 {
        return res
    }
    for i := 1; i < len(nums); i++ {
        curDiff = nums[i] - nums[i-1]
        // 只有第一个数字才有可能出现preDiff等于0的情况
        if (curDiff > 0 && preDiff <= 0) || (curDiff < 0 && preDiff >= 0) {
            res++
            preDiff = curDiff
        }
    }
    return res
}