构造图 Codeforces Round #236 (Div. 2) C. Searching for Graph

题目地址

/*
    题意：要你构造一个有2n+p条边的图，使得，每一个含k个结点子图中，最多有2*k+p条边
    水得可以啊，每个点向另外的点连通，只要不和自己连，不重边就可以，正好2*n+p就结束:)    
*/
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <string>
#include <map>
#include <cmath>
using namespace std;

int main(void)        //Codeforces Round #236 (Div. 2) C. Searching for Graph
{
    //freopen ("B.in", "r", stdin);

    int t;
    scanf ("%d", &t);
    while (t--)
    {
        int n, p;
        scanf ("%d%d", &n, &p);

        int cnt = 0, i = 1, j = 2;
        while (cnt < 2 * n + p)
        {
            printf ("%d %d
", i, j);
            j++;    cnt++;
            if (j == n + 1)    j = ++i + 1;
        }
    }

    return 0;
}