1 #include <stdio.h>

 #include <algorithm>

 #include <stdlib.h>

 #include <time.h>

 using namespace std;

 const int max_rand = ;

 int a[max_rand], b[max_rand];

 struct node

 {

     int x, y;

     bool operator < (const node q) const

     {

         if(x == q.x)

             return y < q.y;

         return x < q.x;

     }

 }RAND[];

 int main()

 {

     for (int i = ; i < max_rand; i ++)

         a[i] = b[i] = i;

     b[] = -;

     int aa = , bb = ;

 //    time_t t;

 //    srand((unsigned) time(&t));

     srand((unsigned)time(NULL));//    let the seed accroding to time

     for (int i = ; i < ; i ++)

     {

         int x = rand()%; //make x between 0 and 2000(include)

         int y = rand()%; //same up;

 /*        double text = (double)rand()/RAND_MAX*(bb-aa) +aa; //produce double text between aa and bb

         printf ("%f\n", text);

         getchar();

 */

         if((!x || !y)||(!a[x] && b[y] == -))

         {

             i --;

             continue;

         }

         RAND[i] = (node){x, y};

         a[x] = ;

         b[y] = -;

     }

     sort(RAND, RAND +);

     for (int i = ; i < ; i ++)

     {

         printf("%d %d\n", RAND[i].x, RAND[i].y);

  //     getchar();

     }

     return ;

 }