【HDU】6043 - KazaQ's Socks（思维）

#include<queue>
#include<cmath>
#include<stack>
#include<cstdio>
#include<vector>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
typedef long long LL;
#define INF 0x3f3f3f3f
#define CLR(a,b) memset(a,b,sizeof(a))
#define PI acos(-1.0)
int main()
{
    LL n,k;
    int Case = 1; 
    while (~scanf ("%lld %lld",&n,&k))
    {
        printf ("Case #%d: ",Case++);
        if (n == 2)
        {
            printf ("%lld\n",((k-1)%2)+1);
            continue;
        }
        if (k <= n)
            printf ("%lld\n",k);
        else
        {
            k -= n - 1;
            LL ant = ((k-1) / (n-1)) + 1;
            LL rest = ((k-1) % (n-1)) + 1;
            if (rest == 1)
                printf ("%lld\n",(ant & 1) ? n : n-1);
            else
                printf ("%lld\n",rest-1);
        }
    }
    return 0;
}