應(yīng)該說是一個純數(shù)學(xué)的題目，考察錯排的概率。
#include <stdio.h>
#define DEBUG 1
int main()
{
#if DEBUG
freopen("C:\\Documents and Settings\\Administrator\\桌面\\in.in","r",stdin) ;
freopen("C:\\Documents and Settings\\Administrator\\桌面\\out.out","w",stdout) ;
#endif
__int64 i, n, sets, s, fenmu ;
double p, temp ;
scanf("%I64d", &sets ) ;
while( sets-- ){
scanf("%I64d", &n ) ;
p = 1 ;
s = 1 ;
fenmu = 1 ;
for( i=1; i<=n; ++i ){
s *= -1 ;
fenmu *= i ;
p += s/(double)fenmu ;
}
printf("%.2lf%%\n", 100*p ) ;
}
}