Testing Round #8 A. IQ Test 水题

题目链接：http://codeforces.com/problemset/problem/328/A

这道题目wa了一次，注意这句话：

You should also print 42 if the next element of progression is not integer. So answer is always integer.

然后就可以了。

 /*
 ID: zypz4571
 LANG: C++
 TASK: iqtest.cpp
  */

 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <cmath>
 #include <cctype>
 #include <algorithm>
 #include <queue>
 #include <set>
 #include <queue>
 #include <list>
 #include <map>
 #define INF 0x3f3f3f3f
 #define mid int m=(l+r)/2
 using namespace std;
 int main ( int argc, char *argv[] )
 {
 #ifndef ONLINE_JUDGE
     freopen("in.txt", "r", stdin);
 #endif
     int a, b, c, d; scanf("%d%d%d%d", &a,&b,&c,&d);
     if(b-a==c-b&&c-b==d-c) printf("%d\n",*d-c);
     else if (b*b==a*c&&b*d==c*c&&(d*d%c==)) printf("%d\n",d*d/c);
     else printf("42\n");
         return EXIT_SUCCESS;
 }                /* ----------  end of function main  ---------- */

==