Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

type Point struct {
	x, y int
}

func main() {
	dx := []int{1, 0, -1, 0}
	dy := []int{0, -1, 0, 1}
	maze := make([][]rune, 30)
	for i := range maze {
		maze[i] = make([]rune, 30)
	}
	next := make([][]rune, 30)
	for i := range next {
		next[i] = make([]rune, 30)
	}
	check := make([][]int, 30)
	for i := range check {
		check[i] = make([]int, 30)
	}
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), " ")
		W, _ := strconv.Atoi(buf[0])
		H, _ := strconv.Atoi(buf[1])
		if W == 0 && H == 0 {
			break
		}
		for i := 0; i < H; i++ {
			scanner.Scan()
			buf_ := scanner.Text()
			for j, v := range buf_ {
				maze[i][j] = v
			}
		}
		man := 0
		for i := 0; i < H; i++ {
			for j := 0; j < H; j++ {
				if maze[i][j] != '.' && maze[i][j] != 'X' && maze[i][j] != '#' {
					switch maze[i][j] {
					case 'E':
						maze[i][j] = 0
						man++
					case 'N':
						maze[i][j] = 1
						man++
					case 'W':
						maze[i][j] = 2
						man++
					case 'S':
						maze[i][j] = 3
						man++
					}
				}
			}
		}
		ans := -1
		for t := 0; t <= 180; t++ {
			if man == 0 {
				ans = t
				break
			}
			for i := 0; i < H; i++ {
				for j := 0; j < W; j++ {
					check[i][j] = 0x7FFFFFFF
				}
			}
			for i := 0; i < H; i++ {
				for j := 0; j < W; j++ {
					if maze[i][j] > 3 {
						continue
					}
					l := (maze[i][j] + 3) % 4
					for k := 0; k < 4; k++ {
						y := i + dy[l]
						x := j + dx[l]
						if 0 <= y && y < H && 0 <= x && x < W && (maze[y][x] == '.' || maze[y][x] == 'X') {
							maze[i][j] = l
							check[y][x] = min(check[y][x], int((l+2)%4))
							break
						}
						l = (l + 1) % 4
					}
				}
			}
			for i := 0; i < H; i++ {
				for j := 0; j < W; j++ {
					next[i][j] = maze[i][j]
				}
			}
			for i := 0; i < H; i++ {
				for j := 0; j < W; j++ {
					if maze[i][j] > 3 {
						continue
					}
					y := i + dy[maze[i][j]]
					x := j + dx[maze[i][j]]
					if 0 <= y && y < H && 0 <= x && x < W && check[y][x] == int((maze[i][j]+2)%4) {
						if maze[y][x] == '.' {
							next[y][x] = maze[i][j]
						} else if maze[y][x] == 'X' {
							man--
						}
						next[i][j] = '.'
					}
				}
			}
			for i := 0; i < H; i++ {
				for j := 0; j < W; j++ {
					maze[i][j]=next[i][j]
				}
			}
		}
		if ^ans != 0 {
			fmt.Println(ans)
		} else {
			fmt.Println("NA")
		}
	}
}

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

C++: #include <iostream>
#include <vector>
#include <cstring>
using namespace std;

int w, h;
int dx[] = {1, 0, -1, 0};
int dy[] = {0, -1, 0, 1};
bool flg[32][32];
char t[32][32];

int main(){
  while(cin >> w >> h, w || h){
    int rem = 0;

    for(int i = 0; i < h; i++){
      cin >> t[i];
      for(int j = 0; j < w; j++){
        if(t[i][j] == 'E') { t[i][j] = 0; rem++; }
        if(t[i][j] == 'N') { t[i][j] = 1; rem++; }
        if(t[i][j] == 'W') { t[i][j] = 2; rem++; }
        if(t[i][j] == 'S') { t[i][j] = 3; rem++; }
      }
    }

    int i;
    int ans = -1;

    for(i = 0; rem != 0 && i <= 180; i++){
      for(int x = 0; x < w; x++){
        for(int y = 0; y < h; y++){
          if(t[y][x] < 4){
            for(int j = 0; j < 4; j++){
              int nd = (t[y][x] + j + 3) % 4;
              int nx = x + dx[nd];
              int ny = y + dy[nd];

              if(4 <= t[ny][nx] && (t[ny][nx] == '.' || t[ny][nx] == 'X')){
                t[y][x] = nd;
                break;
              }
            }
          }
        }
      }

      memset(flg, 0, sizeof(flg));

      for(int x = 0; x < w; x++){
        for(int y = 0; y < h; y++){
          if(t[y][x] == '.' || t[y][x] == 'X'){
            for(int j = 0; j < 4; j++){
              int nx = x + dx[j];
              int ny = y + dy[j];

              if(0 <= nx && nx < w && 0 <= ny && ny < h && t[ny][nx] == (j + 2) % 4 && !flg[ny][nx]){
                flg[ny][nx] = true;
                break;
              }
            }
          }
        }
      }

      for(int x = 0; x < w; x++){
        for(int y = 0; y < h; y++){
          if(flg[y][x]){
            int d = t[y][x];
            int nx = x + dx[d];
            int ny = y + dy[d];

            if(t[ny][nx] == 'X'){
              rem--;
            }
            else{
              t[ny][nx] = d;
            }
            t[y][x] = '.';
          }
        }
      }
    }

    if(i <= 180){
      cout << i << endl;
    }
    else{
      cout << "NA\n";
    }
  }
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <deque>
#include <string>
#include <cmath>
#include <cstdio>
#define FOR(I,A,B) for(int I =(A);I<(B);++I)
#define FORE(I,B) for(int I =1;I<=(B);++I)
#define REP(I,A) FOR(I,0,A)
const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
const char dc[]={'E','N','W','S'};
const char dcc[]={'e','n','w','s'};
using namespace std;

int main() {
	// your code goes here
	int W,H;
	while (cin >> W >> H && W){
	char tmp;
	char maps[32][32]={};
	FORE(i,H)
		FORE(j,W)
			cin >> maps[i][j];
	bool ans;
	int next=0;
	while(true){
		ans=false;
		FORE(j,W)
			FORE(i,H){
				REP(k,4)
					if(maps[i][j]==dc[k]){
						REP(l,4){
							int n=(k+l+3)%4;
							if(maps[i+dy[n]][j+dx[n]]=='.'||maps[i+dy[n]][j+dx[n]]=='X'){
								maps[i][j]=dc[n];
								break;
							}
						}
					ans=true;
					break;
					}
			}
		FORE(i,H)
			FORE(j,W)
				if(maps[i][j]=='.'||maps[i][j]=='X'){
					REP(k,4)
						if(maps[i+dy[k]][j+dx[k]]==dc[(k+2)%4]){

							if(maps[i][j]=='.')
							maps[i][j]=dcc[(k+2)%4];
							maps[i+dy[k]][j+dx[k]]='x';
							break;
						}
				}
		FORE(i,H){
			FORE(j,W){
				if(maps[i][j]=='x')
					maps[i][j]='.';
				REP(k,4)
					if(maps[i][j]==dcc[k])
						maps[i][j]=dc[k];
			//	cout << maps[i][j];
			}
	//	cout << endl;
		}
		if(!ans || next>180)
			break;
		next++;
	}
	if(next>180)
	cout << "NA" << endl;
	else 
	cout << next << endl;
	}
	return 0;
}