程序代码：

#include <stdio.h>
#include <stdlib.h>
#define M 120000

struct Node
{
       int a,b;
}p[M];

int n;

int cmp(const void *a,const void *b)
{
    return ((struct Node*)a)->a-((struct Node*)b)->a;
}

void Calc()
{
     qsort(p+1,n,sizeof(p[0]),cmp);
     
     FILE *f=fopen("2.txt","w");
     
     int i,Pre=1,Max=p[1].b;
     for (i=2; i<=n; i++)
       if (p[i].a<=Max)
       {
                       if (Max<p[i].b) Max=p[i].b;
       }
       else
       {
                       fprintf(f,"%d %d\n",p[Pre].a,Max);
                       Pre=i;
                       Max=p[i].b;
       }
     fprintf(f,"%d %d\n",p[Pre].a,Max);
     fclose(f);
}

void Init()
{
     FILE *f=fopen("1.txt","r");
     char s[30];
     n=0;
     while (fscanf(f,"%[^,]",s)!=EOF)
     {
           sscanf(s,"%d",&p[++n].a);
           fgetc(f);
           fscanf(f,"%[^,]",s);
           sscanf(s,"%d",&p[n].b);
           fgetc(f);
     }
     fclose(f);
}

int main()
{
    Init();
    Calc();
}