Because we only need to find out three increasing numbers.

We only have to keep track of two numbers. One is the smallest

we have come up with and another is the smallest second number

we have met. In the following code, "one" is the smallest and "two"

is the smallest second number. If there is any number larger than

"two" return true.

```
public class Solution {
public boolean increasingTriplet(int[] nums) {
if(nums==null||nums.length<3) return false;
int one = Integer.MAX_VALUE;
int two = Integer.MAX_VALUE;
for(int num:nums){
if(num>one){
if(num>two){
return true;
}else{
two = num;
}
}else{
one = num;
}
}
return false;
}
}
```