HDOJ  1862   EXCEL排序

题目：​​http://acm.hdu.edu.cn/showproblem.php?pid=1862​​

这道题容易TLE，我提交了好多次，最后发现原来是选择判断是用了if而没有用switch，

最后上网找了一下，发现在多次需要判断的情况下，if所用时间要大于switch，

#include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 typedef struct
 {
     int number;
     char name[10];
     int score;
 }student;
 student stu[100100];
 int cmp3(const void *a,const void *b)
 {
     student *aa=(student *)a;
     student *bb=(student *)b;
     if(aa->score!=bb->score)
         return aa->score - bb->score;
     else
         return aa->number-bb->number;
 }
 int cmp2(const void *a,const void *b)
 {
     student *aa=(student *)a;
     student *bb=(student *)b;
     if(strcmp(aa->name,bb->name))
         return strcmp(aa->name,bb->name);
     else
         return aa->number-bb->number;
 }
 int cmp1(const void *a,const void *b)
 {
     student *aa=(student *)a;
     student *bb=(student *)b;
     return aa->number-bb->number;
 }
 int main()
 {
     int n,c,t=1;
     while(scanf("%d%d",&n,&c))
     {
         if(n==0&&c==0)
             break;
         for(int i=0;i<n;i++)
             scanf("%d%s%d",&stu[i].number,stu[i].name,&stu[i].score);
         switch(c)
         {
             case 1:
                 qsort(stu, n, sizeof(stu[0]), cmp1);
                 break;
             case 2:
                 qsort(stu, n, sizeof(stu[0]), cmp2);
                 break;
             case 3:
                 qsort(stu, n, sizeof(stu[0]), cmp3);
                 break;
         }
         printf("Case %d:\n",t++);
         for(int i=0;i<n;i++)
             printf("d %s %d\n",stu[i].number,stu[i].name,stu[i].score);
     }
     return 0;
 }