# Maximum length subsequence with difference between adjacent elements as either 0 or 1 in C++

C++Server Side ProgrammingProgramming

We are given an array of any size and the task is to find the subsequence in the given array with the elements having difference between adjacent elements as 0 or 1.

Input − int arr[] = { 2, 1, 5, 6, 3, 4, 7, 6}

Output − Maximum length subsequence with difference between adjacent elements as either 0 or 1 is − 3

Explanation − The subsequence of adjacent elements in an array with difference as 0 or 1 are {2, 1}. Therefore, the maximum length of subsequence is 2.

Input − int arr[] = { 2, 1, 7, 6, 5}

Output − Maximum length subsequence with difference between adjacent elements as either 0 or 1 is − 3

Explanation − The adjacent elements in an array with difference as 0 or 1 is {7, 6, 5}.. Therefore, the maximum length of subsequence is 3.

## Approach used in the below program is as follows

• Input an array of type integers which can contain positive as well as negative elements.
• Calculate the size of an array and pass an array and size to the function for further functionality.
• Take a temporary array with same size of an input array let’s say temp[size] and another variable maximum and set it to 0
• Start loop for from 0 till size of an array
• Inside the loop, set temp[i] with 1
• Start another loop, from 1 till size
• Inside the loop, start another loop j from 0 till j less than i
• Inside the loop, check if whether adjacent elements with difference 0 or 1 then set temp[i] with temp[i] + 1
• Start loop for from 0 till size
• Inside the loop, check if maximum is less than temp[i] then set maximum = temp[i]
• Return maximum
• Print the result

## Example

Live Demo

#include <bits/stdc++.h>
using namespace std;
//function to calculate the maximum difference
int temp[size], maximum = 0;
for (int i=0; i<size; i++){
temp[i] = 1;
}
for (int i=1; i<size; i++){
for (int j=0; j<i; j++){
if (abs(arr[i] - arr[j]) <= 1 && temp[i] < temp[j] + 1){
temp[i] = temp[j] + 1;
}
}
}
for (int i=0; i<size; i++){
if (maximum < temp[i]){
maximum = temp[i];
}
}
return maximum;
}
int main(){
int arr[] = {1, 5, 3, 7, 8, 9, 2};
int size = sizeof(arr) / sizeof(arr);
cout<<"Maximum length subsequence with difference between adjacent elements as either 0
}
Maximum length subsequence with difference between adjacent elements as either 0 or 1 is: 3