Submission #6069717


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#include <bits/stdc++.h>
  
using namespace std;
  
#define rep(i,n) REP(i,0,n)
#define REP(i,s,e) for(int i=(s); i<(int)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for(int i=(int)(s-1); i>=(int)(e); i--)
#define pb push_back
#define all(r) r.begin(),r.end()
#define rall(r) r.rbegin(),r.rend()
#define fi first
#define se second
  
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 
const int INF = 1e9;
const ll MOD = 1e9 + 7;
double EPS = 1e-8;

int g[110][110];

int main(){
    int n, k;
    cin >> n >> k;
    int ma = (n-1) * (n-2) / 2;
    if(ma < k) {
        cout << -1 << '\n';
        return 0;
    }
    int d = ma - k;
    int m = 0;
    REP(i, 1, n) {
        g[0][i] = 1;
        ++m;
    }
    REP(i, 1, n) REP(j, i+1, n) {
        if(d > 0) {
            g[i][j] = 1;
            --d;
            ++m;
        }
    }
    cout << m << '\n';
    rep(i, n) REP(j, i+1, n) {
        if(g[i][j] == 1) {
            cout << i+1 << " " << j + 1 << '\n';
        }
    }
    return 0;
}

Submission Info

Submission Time
Task E - Friendships
User T1610
Language C++14 (GCC 5.4.1)
Score 500
Code Size 1146 Byte
Status AC
Exec Time 2 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 2 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 1 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 2 ms 256 KB
testcase_16 AC 1 ms 256 KB