1 #include <stdio.h>
 2 #include <algorithm>
 3 #include <stdlib.h>
 4 #include <time.h>
 5 using namespace std;
 6 const int max_rand = 2001;
 7 int a[max_rand], b[max_rand];
 8 struct node
 9 {
10     int x, y;
11     bool operator < (const node q) const
12     {
13         if(x == q.x)
14             return y < q.y;
15         return x < q.x;
16     }
17 }RAND[20010];
18 
19 int main()
20 {
21     for (int i = 0; i < max_rand; i ++)
22         a[i] = b[i] = i;
23     b[0] = -1;
24     int aa = 2, bb = 10;
25 //    time_t t;
26 //    srand((unsigned) time(&t));
27     srand((unsigned)time(NULL));//    let the seed accroding to time
28     for (int i = 0; i < 2000; i ++)
29     {
30         int x = rand()%2001; //make x between 0 and 2000(include)
31         int y = rand()%2001; //same up;
32 /*        double text = (double)rand()/RAND_MAX*(bb-aa) +aa; //produce double text between aa and bb
33         printf ("%f\n", text);
34         getchar();
35 */
36         if((!x || !y)||(!a[x] && b[y] == -1))
37         {
38             i --;
39             continue;
40         }
41         RAND[i] = (node){x, y};
42 
43         a[x] = 0;
44         b[y] = -1;
45     }
46     sort(RAND, RAND +2000);
47     for (int i = 0; i < 2000; i ++)
48     {
49         printf("%d %d\n", RAND[i].x, RAND[i].y);
50  //     getchar();
51     }
52     return 0;
53 }