Design a C$++$ class called Pair which should:

have two public integer member variables: first and second.

provide a constructor that accepts two integers to initialize the first and second variables.

be compatible with the std::sort algorithm for sorting a vector$/$array of Pair objects in the reverse order of std::pair.

$$ be compatible with the std::accumulate algorithm to find the sum of a vector of Pair objects.

$$ std::accumulate should take in a vector$/$array of Pair objects, let's say arrand return a Pair object, say sum, where sum.first represents the sum of arr$[$i$].$first and sum.second represents sum of arr$[$i$].$second $(0\backslash$le i pairs;

pairs.push$\_$back$($Pair$(1,4))$; pairs.push$\_$back$($Pair$(2,4))$; pairs.push$\_$back$($Pair$(2,3))$;

$//$ Old order $=\{\{1,4\},\{2,4\},\{2,3\}\}$

std::sort $($pairs$.$begin$(),$ pairs.end$())$;

$//$ New order $=\{\{2,4\},\{2,3\},\{1,4\}\}$

Pair sum $=$ std::accumulate$($pairs$.$begin$(),$ pairs.end$(),$ Pair$(0,0))$; $//$ sum $=\{2+2+1,4+3+4\}=\{5,11\}$

vector result$(3,$ Pair$(0,0))$;

std::adjacent$\_$difference$($pairs$.$begin$(),$ pairs.end$(),$ result.begin$())$; $//$ result $=\{\{2,4\},\{0,1\},\{-1,1\}\}$

Constraints

$1<=$ number of pairs $<=1000$

$1<=$ pairObj.first, pairObj.second $<=1000$

Sample Input For Custom Testing

STDIN

$3$

number of pairs n $=3$

$2$

elements in a Pair m $=1$

$12$

first Pair $\{1,2\}$

$13$

second Pair $\{1,3\}$

$21$

third Pair $\{2,1\}$

Sample Output

$21$

$13$

$12$

$46$

$21$

$-12$

$0-1$

Explanation

Here n $=3,$

pairs $=[\{2,1),(1,3\},\{1,2\}]$

$$ Sorted $($descending$)$ pairs $=[\{2,1),(1,3),(1,2\}].$

$$ std::accumulate returns sum $=\{2+1+1,1+3+2\}=\{4,6\}.$

$$ Finally result for std::adjacent$\_$difference $=[\{2-0,1-0),(1-2,3-1),(1-1,2-3\}]=[\{2,1\},\{-1,2\},\{0,-1)].$

Sample Input For Custom Testing

$2$

$2$

$13$

$21$

Sample Output

$21$

$13$

$34$

$29$

$13$

$1-2$

Explanation

Here n $=2,$

pairs $=[\{1,3\},\{2,1\}]$

$$ Sorted pairs $=[\{2,1\},\{1,3\}].$

$$ std::accumulate returns sum $=\{3,4\}.$

$$ Finally result for std::adjacent$\_$difference $=[\{1,3\},\{1,-2\}]$