Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
	)

var scanner = bufio.NewScanner(os.Stdin)

const INF = 0x7FFFFFFF

var (
	direction1 = [][]int{ // 奇数段目の移動方向
		{-1, 0}, {1, 0}, {0, -1}, {0, 1}, {1, -1}, {1, 1},
	}
	direction2 = [][]int{ // 偶数段目の移動方向
		{-1, -1}, {0, -1}, {1, 0}, {0, 1}, {-1, 1}, {-1, 0},
	}
)

func main() {
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), " ")
		m, _ := strconv.Atoi(buf[0])
		n, _ := strconv.Atoi(buf[1])
		if m == 0 && n == 0 {
			break
		}
		// initialize district_map
		/*
			district_map = [
				[-1, -1,  -1,  -1,  -1]
				[-1, INF, INF, INF, -1]
				[-1, INF, INF, INF, -1]
				[-1, INF, INF, INF, -1]
				[-1, INF, INF, INF, -1]
				[-1, -1,  -1,  -1,  -1]
			]
		*/
		district_map := make([][]int, n+2)
		for i := range district_map {
			district_map[i] = make([]int, m+2)
		}
		tmp1 := make([]int, m+2)
		for i := range tmp1 {
			tmp1[i] = -1
		}
		district_map[0] = tmp1
		district_map[n+1] = tmp1
		for i := 1; i < n+1; i++ {
			district_map[i] = make([]int, m+2)
			district_map[i][0] = -1
			district_map[i][m+1] = -1
			for j := 1; j < m+1; j++ {
				district_map[i][j] = INF
			}
		}

		scanner.Scan()
		s, _ := strconv.Atoi(scanner.Text())
		for i := 0; i < s; i++ {
			scanner.Scan()
			buf_ := strings.Split(scanner.Text(), " ")
			x, _ := strconv.Atoi(buf_[0])
			y, _ := strconv.Atoi(buf_[1])
			Search(Point{x, y}, district_map, m, n)
		}
		ans := 0
		scanner.Scan()
		t, _ := strconv.Atoi(scanner.Text())
		for i := 0; i < t; i++ {
			scanner.Scan()
			buf__ := strings.Split(scanner.Text(), " ")
			x, _ := strconv.Atoi(buf__[0])
			y, _ := strconv.Atoi(buf__[1])
			z := Count(Point{x, y}, district_map, m, n)
			ans = max(ans, z)
		}
		fmt.Println(ans)
	}
}

func max(a, b int) int {
	if a < b {
		return b
	}
	return a
}

type Point struct {
	x, y int
}

type Entry struct {
	hop   int
	point Point
}

func Search(p Point, mp [][]int, m, n int) {
	que := make([]Entry, 0)
	que = append(que, Entry{0, p})
	check := make([][]bool, n+2)
	for i := range check {
		check[i] = make([]bool, m+2)
	}
	check[p.y][p.x] = true
	mp[p.y][p.x] = 0
	var direction [][]int
	for len(que) > 0 {
		tmp := que[0]
		que = que[1:]
		dist, point := tmp.hop, tmp.point
		if point.y%2 == 0 {
			direction = direction1
		} else {
			direction = direction2
		}
		for _, d := range direction {
			nx, ny := point.x+d[0], point.y+d[1]
			if !check[ny][nx] && mp[ny][nx] != -1 {
				check[ny][nx] = true
				if mp[ny][nx] > dist+1 {
					mp[ny][nx] = dist + 1
				}
				que = append(que, Entry{dist + 1, Point{nx, ny}})
			}
		}
	}
}

func Count(p Point, mp [][]int, m, n int) int {
	que := make([]Entry, 0)
	que = append(que, Entry{0, p})
	check := make([][]bool, n+2)
	for i := range check {
		check[i] = make([]bool, m+2)
	}
	check[p.y][p.x] = true
	ans := 1
	var direction [][]int
	for len(que) > 0 {
		tmp := que[0]
		que = que[1:]
		dist, point := tmp.hop, tmp.point
		if point.y%2 == 0 {
			direction = direction1
		} else {
			direction = direction2
		}
		for _, d := range direction {
			nx, ny := point.x+d[0], point.y+d[1]
			if !check[ny][nx] && mp[ny][nx] != -1 {
				check[ny][nx] = true
				if mp[ny][nx] > dist+1 {
					ans++
				}
				que = append(que, Entry{dist + 1, Point{nx, ny}})
			}
		}
	}
	return ans
}

C++: #include<iostream>
#include<vector>
#include<queue>
#include<functional>

const int INF = 1 << 24;

struct P{
	int x, y;
};

typedef std::pair<P, int> State;

std::vector<P> getPointYouCanGo(int x, int y){
	if(y % 2 == 0){//even
			return {{x-1, y-1}, {x-1, y}, {x-1, y+1}, {x, y-1}, {x, y+1}, {x+1, y}};
	}else{//odd
		return {{x-1, y}, {x, y-1}, {x, y+1}, {x+1, y-1}, {x+1, y}, {x+1, y+1}};
	}
}

template<class T>
std::vector<T> filter(const std::vector<T> v, std::function<bool(T)> cond){
	std::vector<T> result;
	for(auto e : v){
		if(cond(e)){
			result.push_back(e);
		}
	}
	return result;
}

int map[3][100][100], m, n;

void initializeMap(int index, int default_value){
	for(int i=0;i<m;i++){
		for(int j=0;j<n;j++){
			map[index][i][j] = default_value;
		}
	}
}

void createMap(int x, int y){
	std::queue<State> sv;
	map[0][x][y] = 0;
	sv.push(std::make_pair(P{x, y}, 0));
	
	while(!sv.empty()){
		State s = sv.front(); sv.pop();
		P begin_p = s.first;
		int count = s.second;

		std::vector<P> pv = filter<P>(getPointYouCanGo(begin_p.x, begin_p.y), [](P p) -> bool{
				return 0 <= p.x && p.x < m && 0 <= p.y && p.y < n;
			});

		for(const P p : pv){
			if(map[0][p.x][p.y] == -1){
				map[0][p.x][p.y] = count + 1;
				sv.push(std::make_pair(p, count+1));
			}
		}
	}
}

void update(){
	for(int i=0;i<m;i++){
		for(int j=0;j<n;j++){
			map[1][i][j] = std::min(map[1][i][j], map[0][i][j]);
		}
	}
}

int main(){
	int s, t;

	while(std::cin >> m >> n, m){
		initializeMap(1, INF);

		std::cin >> s;
		for(int i=0;i<s;i++){
			int x, y;
			std::cin >> x >> y;
			initializeMap(0, -1);
			createMap(x-1, y-1);
			update();
		}

		int maximumBlocks = 0;
		std::cin >> t;
		for(int k=0;k<t;k++){
			int x, y, blocks = 0;
			std::cin >> x >> y;
			initializeMap(0, -1);
			createMap(x-1, y-1);
			for(int i=0;i<m;i++){
				for(int j=0;j<n;j++){
					if(map[0][i][j] < map[1][i][j]){//win
						blocks++;
					}
				}
			}
			maximumBlocks = std::max(maximumBlocks, blocks);
		}

		std::cout << maximumBlocks << std::endl;
	}
}