Staircase.cpp

//staircase
#include <bits/stdc++.h>

using namespace std;

string ltrim(const string &);
string rtrim(const string &);

/*
 * Complete the 'staircase' function below.
 *
 * The function accepts INTEGER n as parameter.
 */
//n-1-i times space and i+1 times #
void staircase(int n) {
    for(int i=0;i<=n-1;++i){
        for(int j=0;j<=n-1;++j)
        {
            if(j>=n-1-i)
            cout<<"#";
            else cout<<" ";
        }
        cout<<"\n";
    }

}

int main()
{
    string n_temp;
    getline(cin, n_temp);

    int n = stoi(ltrim(rtrim(n_temp)));

    staircase(n);

    return 0;
}

string ltrim(const string &str) {
    string s(str);

    s.erase(
        s.begin(),
        find_if(s.begin(), s.end(), not1(ptr_fun<int, int>(isspace)))
    );

    return s;
}

string rtrim(const string &str) {
    string s(str);

    s.erase(
        find_if(s.rbegin(), s.rend(), not1(ptr_fun<int, int>(isspace))).base(),
        s.end()
    );

    return s;
}