WA in ONE23

general
1

Why did this not work for the problem ONE23 in FULU20

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define mod 1000000007

void solve();
signed main()
{
    int t = 1;
    // cin >> t;
    while(t--)
        solve();
}
void solve()
{
    int n;
    cin >> n;
    cout << (n + n*n + n*n*n)%mod;
}

@jains8844

2

bro take n to long long :slight_smile:

4

no when we cube of no. upto 10^5 it will overflow :slight_smile:

5

See the macros
He define int as long long.

1 Like
6

q .link : CodeChef: Practical coding for everyone
@ssjgz

7

why the above approach fails?

8

you have to take modulus seperately for n, nn, nn*n and then take final modulus

9

but why ?
if i take max n = 10^5
then n*n = 10^10
n * n * n = 10^15
10^5+10^10+10^15 = 1000010000100000
1000010000100000 < 10^18 (upper limit of long long)
then why it is wrong?

10

read this article. solution of your every doubt
link: Modulo 10^9+7 (1000000007) - GeeksforGeeks

11

Nah bro this article is different here at max the no is less than 10^16 still it gives WA ?