Java implementation for Triple sequence LeetCode 334 increments

334. incremental ternary sequence

Given an unsorted array, the array is determined whether or not there is increasing subsequence length of 3.

Mathematical expressions are as follows:

If there is such i, j, k, and satisfies 0 ≤ i <j <k ≤ n-1,
so that arr [i] <arr [j ] <arr [k], returns true; otherwise returns false.
Description: The time requirements of the algorithm complexity is O (n), the spatial complexity is O (1).

Example 1:

Input: [1,2,3,4,5]
Output: true
Example 2:

Input: [5,4,3,2,1]
Output: false

class Solution {
      public boolean increasingTriplet(int[] nums) {
        if (nums==null||nums.length<3) return false;
        int big=Integer.MAX_VALUE,small=Integer.MAX_VALUE;
        for (int i:nums){
            // 通过if的结构保证递增！
            if (i<=small) small=i;
            // 走到这一步说明这个值大于前面的值(i>small)
            else if (i<=big) big=i;
            // 走到这一步说明这个值大于前面的两个值（i>big>small）
            else return true;
        }
        return false;
    }
}