poj 3601 Tower of Hanoi

#include <stdio.h>#define N 101int main(){    int a[N] = {0}, ///最下面一种盘 反向        b[N] = {0}, ///最下面一种盘 正向        s[N],m,n;    while(scanf("%d%d",&n,&m) != EOF)    {        int i,j;        for(i = 1; i <= n; ++i) scanf("%d",&s[i]);        a[1] = s[1] % m;        b[1] = (2 * s[1] - 1) % m;        for(i = 2; i <= n; ++i)        { a[i] = ( (a[i-1] << 1) + s[i]) % m; if(s[i] == 1)     b[i] = a[i]; else     b[i] = (b[i-1] + (a[i-1]<<1) + (s[i]<<1)) % m;///a方法移两次便正向了        }        printf("%dn",b[n]);    }    return 0;}