334. Increasing Triplet Subsequence | Leetcode solution

334. Increasing Triplet Subsequence

 Given an integer array nums, return true if there exists a triple of indices (i, j, k) such that i < j < k and nums[i] < nums[j] < nums[k]. If no such indices exists, return false.

 

Example 1:

Input: nums = [1,2,3,4,5]
Output: true
Explanation: Any triplet where i < j < k is valid.

Example 2:

Input: nums = [5,4,3,2,1]
Output: false
Explanation: No triplet exists.

Example 3:

Input: nums = [2,1,5,0,4,6]
Output: true
Explanation: The triplet (3, 4, 5) is valid because nums[3] == 0 < nums[4] == 4 < nums[5] == 6.

 

Constraints:

• 1 <= nums.length <= 5 * 105
• -231 <= nums[i] <= 231 - 1

solution:

class Solution {

public:

    bool increasingTriplet(vector<int>& nums) {

         

          int left = INT_MAX;

          int mid = INT_MAX;

        for(int i =0 ; i < nums.size() ; i++)

        {    

            if(nums[i] > mid)

                return true;

            else

             if(nums[i] < left)

                 left = nums[i];

            else

            if( nums[i] > left && nums[i] < mid)

                mid = nums[i];

            

        }

        return false;

    }

};