Analyze Algorithm 3.7 and show that it has a linear-time complexity

//////////////////////////////////////////////////////Algorithm 3.7///////////////////////////////////////////

void order (index i, index j)

{

if( i == j)

cout << "A" << i

else {

k = P[i][j];

cout << "(";

order (i,k);

order(k+1, j);

cout << ")" ;

}

}