Palindrome quiz

#include <stdio.h>
#include <iostream>
#include <memory.h>
#include <string>
#include <algorithm>
#include <vector>
using namespace std;

#define sqr(a) ((a) * (a))
#define pi 3.1415926535897932384626433832795

#define TASK "k"
//#define CONTEST 1

string s;

void Load()
{
	getline(cin, s);
}

void Solve()
{
	int i = 0, j = s.length()-1;
	bool ok = true;
	while (i <= j)    
	{
		if(!isalpha(s[i]))
		{
			i++;
			continue;
		}

		if(!isalpha(s[j]))
		{
			j--;
			continue;
		}

		if(tolower(s[i]) != tolower(s[j]))
		{
			ok = false;
			break;
		}
		i++;
		j--;
	}

	if (ok)
		cout << "YES" << endl;
	else
		cout << "NO" << endl;
}                 

int main()
{
#ifdef CONTEST
	freopen(TASK".in", "r", stdin);
	freopen(TASK".out", "w", stdout);
#endif
	
	Load();
	Solve();

	return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED