Google Code Jam 2013 Round 1C, Task B

#include<cstdio>
#include<algorithm>
#include<string>
#include<iostream>

using namespace std;

int T, x, y, m, l;
string s;

void foo (int x, int y, int ans)
{
    if (ans == 0)
        return;
    int m1 = abs(x - ans) + abs(y);
    int m2 = abs(x + ans) + abs(y);
    int m3 = abs(x) + abs(y - ans);
    int m4 = abs(x) + abs(y + ans);
    if (m1 <= m2 && m1 <= m3 && m1 <= m4)
    {
        s += 'E';
        foo (x - ans, y, ans - 1);
    }
    if (m2 < m1 && m2 <= m3 && m2 <= m4)
    {
        s += 'W';
        foo (x + ans, y, ans - 1);
    }
    if (m3 < m1 && m3 < m2 && m3 <= m4)
    {
        s += 'N';
        foo (x, y - ans, ans - 1);
    }
    if (m4 < m1 && m4 < m2 && m4 < m3)
    {
        s += 'S';
        foo (x, y + ans, ans - 1);
    }
}

int main()
{
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    scanf("%d", &T);
    for (int g = 0; g < T; g++)
    {
        s = "";
        printf("Case #%d: ", g + 1);
        scanf("%d%d", &x, &y);
        m = abs(x) + abs(y);
        for (int i = 1; i < 10000; i++)
            if (i * (i + 1) / 2 >= m)
            {
                l = i;
                break;
            }
        while ((l * (l + 1) / 2) % 2 != m % 2)
            l++;
        foo(x, y, l);
        reverse(s.begin(), s.end());
        cout << s << endl;
    }
    return 0;
}