思路:記錄兩個值,一個small,一個big。遍歷數組,如果小於small,則更新small,不然如果小於big,則更新big,如果大於big,則存在遞增三元子序列
bool increasingTriplet(vector<int>& nums) {
int small = INT32_MAX;
int big = INT32_MAX;
int i = 0;
while (i < nums.size()) {
if (nums[i] <= small)
small = nums[i];
else if (nums[i] > small && nums[i] <= big)
big = nums[i];
else
return true;
i++;
}
return false;
}