N1VALUES - Editorial

editorial
, ,
4

What’s the problem with this solution:

#include<bits/stdc++.h>
using namespace std;

#define ll long long

void solve(){
int n;
cin >> n;
ll sum = 0;
ll a = pow(2, n);

for(ll i = 0; i < n-1; i++){
    sum += i;
}

sum += 2*(n-1);

ll b = a - sum;

for(int i=1; i < n-1; i++){
    cout << i << " ";
}

cout << n-1 << " " << n-1 << " " << b;

cout << "\n";

}

int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);

 int t;
 cin >> t;

 while(t--){
     solve();
 }

return 0;

}

5

Please refer the video editorial for better understanding.

1 Like
6

why this this isn’t working?, Using the same approach.

7

You have to print in increasing order.
This code printing 1 at the end.

8 
t = int(input())
for i in range(t):
    n = int(input())
    sum=0
    l=[]
    for i in range(1,n):
        l.append(i)
        sum+=i
    l.append(n-1)
    sum+=(n-1)
    l.append((2**n)-sum)
    print(*l)
9

what is wrong in this code? pls tell

10

cout << ( 1LL << i ) << " \n"[ i == n - 1 ] ;

In the testers code. How does this link work. Is there some kind of conditnal printing here
@ronniechonev

11

For n = 1, your output is

0 2

which is wrong because the statement asks for positive integers.

2 Likes
12

Treat " \n" as a string of length 2, then you can see that " \n"[ i == n - 1 ] prints a space when i is not n-1 and prints a newline when it is.

3 Likes
13

That’s a crazy way of handling the output format.

1 Like
14

This code satisfie all conditions still it’s wrong, why? Please help me to rectify my mistake in it.

#include <bits/stdc++.h>
using namespace std;
int main()
{
int t;
cin >> t;
while (t–)
{
int n;
cin >> n;
long long int a[61];
a[0] = 1;
a[1] = 1;
int sum = 2;
for (int i = 2; i <= n - 1; i++)
{
a[i] = i;
sum = sum + a[i];
}
if (n != 1)
{
a[n] = pow(2, n) - sum;
}
for (int i = 0; i <= n; i++)
{
cout << a[i] << " ";
}
cout << endl;
}
return 0;
}

15

here u can check for a case n=1 print “1 1”(its not taking 0 as positive integer here)

16

Please help, I’m still not able to understand. Why the above solution is not getting accepted.

The solution can be find below as well as here.

#include <bits/stdc++.h>
using namespace std;

int main() {
	int t; cin >> t;
	while (t--) {
	    int n; cin >> n;
	    int sum = pow(2, n) - 2;
	    cout << "1 1";
        int counter = 2;
        for (int i = 1; i < n - 1; i++) {
            cout << " " << counter;
            sum -= counter;
            counter++;
        }
        if (n != 1) cout << " " << sum;
 	    if (t != 0) cout << endl;
	}
	return 0;
}

For input:

6
1
2
3
4
5
6

Output is correct:

1 1
1 1 2
1 1 2 4
1 1 2 3 9
1 1 2 3 4 21
1 1 2 3 4 5 48

But still shows wrong answer. @ssjgz @sharad_0_1

17

Always test the boundary values!

[simon@simon-laptop][09:41:57]
[~/devel/hackerrank/otherpeoples]>./compile-latest-cpp.sh 
Compiling heatherstanton-N1VALUES.cpp
Executing command:
  g++ -std=c++17 heatherstanton-N1VALUES.cpp -O3 -g3 -Wall -Wextra -Wconversion -DONLINE_JUDGE -D_GLIBCXX_DEBUG    -fsanitize=undefined -ftrapv
heatherstanton-N1VALUES.cpp: In function ‘int main()’:
heatherstanton-N1VALUES.cpp:8:26: warning: conversion to ‘int’ from ‘__gnu_cxx::__promote_2<int, int, double, double>::__type {aka double}’ may alter its value [-Wfloat-conversion]
      int sum = pow(2, n) - 2;
                ~~~~~~~~~~^~~
^R
Successful
[simon@simon-laptop][09:42:03]
[~/devel/hackerrank/otherpeoples]>echo "1
60" | ./a.out 
heatherstanton-N1VALUES.cpp:13:17: runtime error: signed integer overflow: -2147483648 - 2 cannot be represented in type 'int'
1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 2147481879
1 Like
18

I got my mistake!! i needed to use long long int…now it’s work

19 
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

void solve()
{
    int n;
    cin>>n;
    ll k=1;
    vector<ll>v;
    for(int i=1;i<=n+1;i++){
        if(i==1||i==2)
            v.push_back(1);
        else
            v.push_back(pow(2,k++));
    }
    for(int i:v)
        cout<<i<<" ";
    cout<<"\n";
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t;
    cin>>t;
    while(t--)
        solve();
    return 0;
}

why I am getting WA? please help.

20

here you go

#include <bits/stdc++.h>

using namespace std;

int main() {

int t; cin >> t;

while (t--) {

    long long int n; cin >> n;

    long long int pw=pow(2,n);

    long long int sum =  pw- 2;

    cout << "1 1";

    long long int counter = 2;

    for (int i = 1; i < n - 1; i++) {

        cout << " " << counter;

        sum -= counter;

        counter++;

    }

    if (n != 1) cout << " " << sum;

    if (t != 0) cout << endl;

}

return 0;

}

1 Like
21

bro can you pls tell y i am getting WA?

#include
#include<math.h>
#include
#include
using namespace std;
long long i,k;
void solve(){
long long n,power; cin>>n; vectorv;
for(i=1;i<n;i++){
if(i<=n)
v.push_back(i);
if(i==n-1){v.push_back(i);}

}
int k= accumulate(v.begin(),v.end(),0);

int po= 1ll<<n;
int m=po-k;
v.push_back(po-k);

   for(int i=0;i<n+1;i++)cout<<v[i]<<" ";
   cout<<"\n";

}
int main(){
ios::sync_with_stdio(false); cin.tie(NULL);
int tc; cin>>tc;
while(tc–>0)solve();
return 0;
}

22

@harshkumar007 @arikaran_02 both of yours fail on this testcase:

23

ok bro thnx

2 Likes