Submission #6063110


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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define ft first
#define sd second
#define fr(i,n) for(int i=0;i<(n);++i)
#define Fr(i,n) for(int i=1;i<=(n);++i)
#define ifr(i,n) for(int i=(n)-1;i>=0;--i)
#define iFr(i,n) for(int i=(n);i>0;--i)

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n,k;
    cin>>n>>k;
    int a=((n-1)*(n-2))/2;
    if(k>a){
        cout<<-1<<endl;
        return 0;
    }
    cout<<n-1+a-k<<endl;
    Fr(i,n-1){
        cout<<i<<" "<<n<<endl;
    }
    int c=a-k;
    Fr(i,n-1){
        Fr(j,i-1){
            if(c==0) return 0;
            cout<<i<<" "<<j<<endl;
            --c;
        }
    }
}

Submission Info

Submission Time
Task E - Friendships
User Motsu_xe
Language C++14 (GCC 5.4.1)
Score 500
Code Size 706 Byte
Status AC
Exec Time 9 ms
Memory 256 KB

Judge Result

Set Name All Sample
Score / Max Score 500 / 500 0 / 0
Status
AC × 18
AC × 2
Set Name Test Cases
All sample_01, sample_02, testcase_01, testcase_02, testcase_03, testcase_04, testcase_05, testcase_06, testcase_07, testcase_08, testcase_09, testcase_10, testcase_11, testcase_12, testcase_13, testcase_14, testcase_15, testcase_16
Sample sample_01, sample_02
Case Name Status Exec Time Memory
sample_01 AC 1 ms 256 KB
sample_02 AC 1 ms 256 KB
testcase_01 AC 1 ms 256 KB
testcase_02 AC 1 ms 256 KB
testcase_03 AC 1 ms 256 KB
testcase_04 AC 9 ms 256 KB
testcase_05 AC 1 ms 256 KB
testcase_06 AC 1 ms 256 KB
testcase_07 AC 1 ms 256 KB
testcase_08 AC 1 ms 256 KB
testcase_09 AC 1 ms 256 KB
testcase_10 AC 2 ms 256 KB
testcase_11 AC 1 ms 256 KB
testcase_12 AC 1 ms 256 KB
testcase_13 AC 1 ms 256 KB
testcase_14 AC 1 ms 256 KB
testcase_15 AC 9 ms 256 KB
testcase_16 AC 1 ms 256 KB