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 <iomanip>
#include <string>
#include <sstream>
#include <algorithm>
#include <vector>
#include <utility>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <functional>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cassert>
 
using namespace std;
 
#define REP(i,s,e) for(int i=(s); i<(int)(e); i++)
#define rep(i,n) REP(i, 0, n)
#define pb push_back
#define mp make_pair
#define all(r) (r).begin(),(r).end()
#define rall(r) (r).rbegin(),(r).rend()
#define fi first
#define se second
 
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef vector<ll> vl;
typedef vector<vl> vll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 

 
const int INF = 1e9;
const double EPS = 1e-8;
const int mod = 1e9 + 7;
const ll LINF = 1e18;
const double PI = acos(-1);

struct Input
{
	int n;
	char c;
	char str[1024];
	string s;
	ll l;
	int nextInt(){
		scanf("%d", &n);
		return n;
	}
	ll nextLong(){
		scanf("%lld", &l);
		return l;
	}
	char nextChar(){
		scanf("%c", &c);
		return c;
	}
	string next(){
		scanf("%s", str);
		return string(str);
	}
	string nextLine(){
		getline(cin, s);
		return s;
	}
};
Input in;


int dx1[]={-1,-1,0,+1,0,-1};
int dy1[]={0,-1,-1,0,+1,+1};
int dx2[]={-1,0,+1,+1,+1,0};
int dy2[]={0,-1,-1,0,+1,+1};

int d[110][110];
bool used[110][110];

bool isOutOfRange(int x, int y, int w, int h){
	if(x <= 0 || y <= 0 || x > w || y > h) return true;
	return false;
}

int main(){
	while(1){
		int w = in.nextInt(), h = in.nextInt();
		if(w == 0 && h == 0) break;
		int s = in.nextInt();
		queue<pii> q;
		rep(i, 110) rep(j, 110) d[i][j] = INF;
		rep(i, s){
			int a = in.nextInt(), b = in.nextInt();
			q.push(mp(0, a * 1000 + b));
			d[a][b] = 0;
		}

		while(!q.empty()){
			int x = q.front().se / 1000, y = q.front().se % 1000, c = q.front().fi; q.pop();
			//cout<<x<<" "<<y<<" "<<c<<endl;
			rep(i, 6){
				int nx = x + ((y & 1) ? dx1[i] : dx2[i]);
				int ny = y + ((y & 1) ? dy1[i] : dy2[i]);
				//cout<<" "<<nx<<" "<<ny<<endl;
				if(isOutOfRange(nx, ny, w, h) || d[nx][ny] <= c + 1) continue;

				d[nx][ny] = c + 1;
				q.push(mp(c + 1, nx * 1000 + ny));
			}
		}

		int t = in.nextInt(), ans = 0;
		rep(i, t){
			int a = in.nextInt(), b = in.nextInt(), tmp = 1;
			q.push(mp(0, a * 1000 + b));
			//vector<vector<int> > v(w + 1, vi(h + 1, 0));
			rep(i, w + 1) rep (j, h + 1) used[i][j] = false;
			while(!q.empty()){
				int x = q.front().se / 1000, y = q.front().se % 1000, c = q.front().fi; q.pop();
				rep(i, 6){
					int nx = x + ((y & 1) ? dx1[i] : dx2[i]);
					int ny = y + ((y & 1) ? dy1[i] : dy2[i]);
					if(isOutOfRange(nx, ny, w, h) || d[nx][ny] <= c + 1 || used[nx][ny]/*v[nx][ny] == 1*/) continue;

					tmp++;
					//v[nx][ny] = 1;
					used[nx][ny] = true;
					q.push(mp(c + 1, nx * 1000 + ny));
				}
			}
			ans = max(ans, tmp);
		}
		printf("%d\n", ans);

		// rep(i, h){
		// 	rep(j, w){
		// 		if(j & 1) printf("%2d  ", d[j][i]);
		// 		else printf("  %2d", d[j][i]);
		// 	}
		// 	printf("\n");
		// }
	}
}

C++: #include<cstdio>
#include<cstring>
#include<utility>
#include<algorithm>
#include<queue>
using namespace std;
typedef struct pos
{
	int x,y,cost;
	bool operator ()(pos const& a, pos const& b) const
	{
		return a.cost>b.cost;
	}

}pos;

int M,N,S,T,m[101][101],i,j,p,q,R,t;

int bfs(int x,int y,int abj)
{
	int i,c=1,mx[2][6]={{-1,0,1,0,-1,-1},{0,1,1,1,0,-1}},
			  my[2][6]={{-1,-1,0,1,1,0},{-1,-1,0,1,1,0}};
	priority_queue<pos,vector<pos>,pos>Q;
	m[y][x]=0;
	pos tmp={x,y,0};
	Q.push(tmp);
	while(!Q.empty())
	{
		tmp=Q.top();Q.pop();
		for(i=0;i<abj;i++)
		{
			if(0<=tmp.y+my[tmp.y%2][i]&&tmp.y+my[tmp.y%2][i]<N&&0<=tmp.x+mx[tmp.y%2][i]&&tmp.x+mx[tmp.y%2][i]<M)
				if(m[tmp.y+my[tmp.y%2][i]][tmp.x+mx[tmp.y%2][i]]>tmp.cost+1)
				{
					m[tmp.y+my[tmp.y%2][i]][tmp.x+mx[tmp.y%2][i]]=tmp.cost+1;
					pos tmp2={tmp.x+mx[tmp.y%2][i],tmp.y+my[tmp.y%2][i],tmp.cost+1};
					c++;
					Q.push(tmp2);
				}
		}
	}
	return c;
}

int main()
{
	for(i=0;i<105;i++)
		for(j=0;j<105;j++)
		{

		}
	for(;~scanf("%d%d%d",&M,&N,&S),M;)
	{
		memset(m,0x7,sizeof(m));
		for(i=0;i<S;i++)
		{
			scanf("%d%d",&p,&q);
			bfs(p-1,q-1,6);
		}
		for(R=0,scanf("%d",&T),j=0;j<T;j++)
		{
			scanf("%d%d",&p,&q);
			t=bfs(p-1,q-1,6);
			R=t<R?R:t;
		}
		printf("%d\n",R);
	}
	return 0;
}