SortedSubsequence.cpp

// C++ Program for above approach
#include <bits/stdc++.h>
using namespace std;

// Function to find the triplet
void find3Numbers(vector<int>& nums)
{
	
// If number of elements < 3
// then no triplets are possible
if (nums.size() < 3){
	cout << "No such triplet found";
	return;
}
	
// track best sequence length
// (not current sequence length)
int seq = 1;		
	
// min number in array
int min_num = nums[0];
	
// least max number in best sequence
// i.e. track arr[j] (e.g. in
// array {1, 5, 3} our best sequence
// would be {1, 3} with arr[j] = 3)
int max_seq = INT_MAX;	
	
// save arr[i]
int store_min = min_num;
	
// Iterate from 1 to nums.size()
for (int i = 1; i < nums.size(); i++)
{
	if (nums[i] == min_num)
	continue;
	
	else if (nums[i] < min_num)
	{
	min_num = nums[i];
	continue;
	}
	
	// this condition is only hit
	// when current sequence size is 2
	else if (nums[i] < max_seq) {	
		
	// update best sequence max number
	// to a smaller value
	// (i.e. we've found a
	// smaller value for arr[j])
	max_seq = nums[i];	
		
	// store best sequence start value
	// i.e. arr[i]
	store_min = min_num;			
	}
	
	// Increase best sequence length &
	// save next number in our triplet
	else if (nums[i] > max_seq)
	{
	// We've found our arr[k]!
	// Print the output		
		cout << "Triplet: " << store_min <<
				", " << max_seq << ", " <<
						nums[i] << endl;
		return;
	}
}
	
// No triplet found
cout << "No such triplet found";
}

// Driver Code
int main() {
vector<int> nums {1,2,-1,7,5};
	
// Function Call
find3Numbers(nums);
}