题意:给一组数字,如果这组数据中含有a而且还含有2a,则cnt++。(用哈希比较简单)
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main()
{
int s[1000]={0}, t, i;
int ans = 0;
while(scanf("%d", &t) && (t+1)!=0)
{
ans = 0;
memset(s, 0, sizeof(s));
s[t] = 1;
while(scanf("%d", &t) && t!=0 ){
s[t] = 1;
}
for(i=0; i<99; i++){
if(s[i*2] && s[i])
ans++;
}
printf("%d\n", ans);
}
return 0;
}