poj 1013(uva 608) Counterfeit Dollar

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

#define FOR(i,s,t) for (int i = s; i < t; ++i)
#define MEM(s,v) memset(s, v, sizeof(s))

#define EPS 1e-8
#define _N 15
#define _M 105
#define PI acos(-1.0)

int even[12], light[12], heavy[12];
char l[_N], r[_N], b[_N];

void set_union(int *a, char *b) 
{
    FOR (i, 0, strlen(b)) { a[b[i] - 'A'] += 1; }
}

int main()
{
    int n; scanf("%d", &n); while (n--) {
        MEM (even, 0); MEM (light, 0); MEM (heavy, 0);
        FOR (i, 0, 3) {
            scanf("%s%s%s", l, r, b);
            if (b[0] == 'e') {
                set_union(even, l);
                set_union(even, r);
            } else if (b[0] == 'u') {
                set_union(heavy, l);
                set_union(light, r);
            } else {
                set_union(light, l);
                set_union(heavy, r);
            }
        }
        int _l[12], _h[12];
        FOR (i, 0, 12) {
            _l[i] = light[i] * (!even[i] && light[i]);
            _h[i] = heavy[i] * (!even[i] && heavy[i]);
        }
        int max_c = 0, max_n = 0, _t = 0;
        FOR (i, 0, 12) if (_l[i] > max_n) {
            max_c = i; max_n = _l[i]; _t = -1;
        }
        FOR (i, 0, 12) if (_h[i] > max_n) {
            max_c = i; max_n = _h[i]; _t = 1;
        }
        printf("%c is the counterfeit coin and it is %s.\n", max_c + 'A', _t == -1 ? "light" : "heavy");
    }
    return 0;
}