题目：

题解：

int wiggleMaxLength(int* nums, int numsSize) {
    if (numsSize < 2) {
        return numsSize;
    }
    int prevdiff = nums[1] - nums[0];
    int ret = prevdiff != 0 ? 2 : 1;
    for (int i = 2; i < numsSize; i++) {
        int diff = nums[i] - nums[i - 1];
        if ((diff > 0 && prevdiff <= 0) || (diff < 0 && prevdiff >= 0)) {
            ret++;
            prevdiff = diff;
        }
    }
    return ret;
}