boolean piecesContiguous(Side player) {
        HashMap<Integer, Integer> set;
        set = player == WHITE ? _whiteSetMap : _blackSetMap;
        int prev = 0;
        for (int v : set.values()) {
            if (prev == 0) {
                prev = v;
            }
            if (prev != v) {
                return false;
            }
        }
        return true;
    }