Codeforces Round #260 (Div. 2) b. Fedya and Maths

The problem is to find a regular problem, just start a look very Mongolian;

Then I pushed myself a bit, 1^n,2^n,3^n,4^n their single digit will change with the increase of N, wherein 2 and 3 of the cycle section is the 4;4 cycle is 2;

This will be able to launch their and MOD5 number is in the 0,0,0,4 cycle, that is, to determine whether a number can be divisible by 4, if you can output 4, otherwise output 0;

Determine whether it can be divisible by 4: only need to determine whether the number of two digits can be divisible by 4;

#include <cstdio>
#include <cstring>
#include <cmath>
#include <climits>
# include<cctype>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <queue>
#include <vector>
#include <map>
#include <set>
# include<string>
#include <stack>
#define LL Long long 
#define MAX 100010
#define INF Int_max
#define EPS 1e-8

using namespace std;

Char S[max];

int main () {while
	(scanf ("%s", s)! = EOF) {
		int len = strlen (s), a = 0;
		if (len = = 1) {
			a = a + s[len-1]-' 0 ';
		}
		else{
			A = a*10 + s[len-2]-' 0 ';
			A = a*10 + s[len-1]-' 0 '; 
		}	printf ("a =%d\n", a);
		If (a% 4 = = 0) printf ("%d\n", 4);
		else printf ("%d\n", 0);
	}
	return 0;
}