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

 1 /*
 2     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
 3     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:)    
 4 */
 5 #include <cstdio>
 6 #include <iostream>
 7 #include <algorithm>
 8 #include <cstring>
 9 #include <string>
10 #include <map>
11 #include <cmath>
12 using namespace std;
13 
14 int main(void)        //Codeforces Round #236 (Div. 2) C. Searching for Graph
15 {
16     //freopen ("B.in", "r", stdin);
17 
18     int t;
19     scanf ("%d", &t);
20     while (t--)
21     {
22         int n, p;
23         scanf ("%d%d", &n, &p);
24 
25         int cnt = 0, i = 1, j = 2;
26         while (cnt < 2 * n + p)
27         {
28             printf ("%d %d\n", i, j);
29             j++;    cnt++;
30             if (j == n + 1)    j = ++i + 1;
31         }
32     }
33 
34     return 0;
35 }