Divisibility

http://162.105.81.212/JudgeOnline/problem?id=1745

第二次挤进第一版，同时挤进一千，从Dominoes和Coins得到的启示，k同余等价类，每次状态只在除k余数相同的数之间转移

#include <iostream>using namespace std ;int n , k , num[110] ;bool f[110] ;void Readin (){int i , sum , v ; scanf ("%d%d" , &n , &k) ;memset (num , 0 , sizeof (num)) ;memset (f , false , sizeof (f)) ;for (i = sum = 0 ; i < n ; i ++){scanf ("%d" , &v) ;v = abs (v) ;sum += v ;num[(v << 1) % k] ++ ;}sum %= k ;if (sum)sum = k - sum ;f[sum] = true ;}void Comp (){int i , j , a[110] ;bool update ;for (i = 1 ; i < k && !f[0] ; i ++)if (num[i]){for (j = 0 ; j < k ; j ++)if (f[j])a[j] = num[i] ;elsea[j] = 0 ;update = true ;while (update){update = false ;for (j = 0 ; j < k ; j ++)if (!f[j] && a[(j + k - i) % k]){f[j] = update = true ;a[j] = a[(j + k - i) % k] - 1 ;}}}if (f[0])printf ("Divisible/n") ;elseprintf ("Not divisible/n") ;}int main (){Readin () ;Comp () ;return 0 ;}