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;
}