Using Queen to solve the math puzzle "SEND + MORE = MONEY"

SendMoreMoney.java

final int m = 1;
List<Integer> answer = range(9, 0).except(m).permutations(7).first(new Predicate<List<Integer>>() {
    @Override
    public boolean evaluate(final List<Integer> perm) {
        int s = perm.get(0);
        int e = perm.get(1);
        int n = perm.get(2);
        int d = perm.get(3);
        int o = perm.get(4);
        int r = perm.get(5);
        int y = perm.get(6);
        return _(s, e, n, d) + _(m, o, r, e) == _(m, o, n, e, y);
    }

    private int _(int a, int b, int c, int d) {
        return 1000 * a + 100 * b + 10 * c + d;
    }

    private int _(int a, int b, int c, int d, int e) {
        return _(a, b, c, d) * 10 + e;
    }
}).getOrElse(Collections.<Integer>emptyList());