Problem E: Erratic Ants

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <map>
#include <cmath>
#include <cstring>
#include <string>
#include <queue>
#include <stack>
#include <cctype>

const double Pi = atan(1) * 4;
using namespace std;

int graph[200][200];
bool through[100][100];
int dr[] = {1,-1,0,0};
int dc[] = {0,0,-1,1};
bool visit[200][200];
struct Point{
    int x,y;
    int step;
    Point(){
        step = 0;
    }
    Point(int xx,int yy,int tt):x(xx),y(yy),step(tt){}
};
int main()
{
    freopen("input.in","r",stdin);
    //freopen("output.in","w",stdout);
    int t;
    cin >> t;
    queue<Point>que;
    while(t--){
        int n;
        cin >> n;
        memset(graph,0,sizeof(graph));
        memset(through,0,sizeof(through));
        memset(visit,0,sizeof(visit));
        int x = 100;
        int y = 100;
        int sx = 100;
        int sy = 100;
        graph[x][y] = 1;
        char ch;
        int ww = n;
        while(n--){
            cin >> ch;
            int xx = x;
            int yy = y;
            if(ch == ‘E‘){
                xx++;
            }
            else if(ch == ‘W‘){
                xx--;
            }
            else if(ch == ‘S‘){
                yy--;
            }
            else if(ch == ‘N‘){
                yy++;
            }
            if(!graph[xx][yy])
                graph[xx][yy] = graph[x][y]+1;
            through[ graph[x][y] ][graph[xx][yy] ] = 1;
            through[ graph[xx][yy] ][graph[x][y] ] = 1;
            x = xx;
            y = yy;
        }
        if(ww == 1){
            cout << "1" << endl;
            continue;
        }
        while(!que.empty()){
            que.pop();
        }
        Point head(sx,sy,0);
        que.push(head);
        visit[sx][sy] = 1;
        while(!que.empty()){
            Point tmp = que.front();
            que.pop();
            if(tmp.x == x && tmp.y == y){
                cout << tmp.step << endl;
                break;
            }
            for(int i = 0;i < 4;i++){
                int xx = tmp.x + dr[i];
                int yy = tmp.y + dc[i];
                if(graph[xx][yy] != 0 && through[  graph[tmp.x][tmp.y] ][ graph[xx][yy] ] && !visit[xx][yy]){
                    Point tt(xx,yy,tmp.step+1);
                    que.push(tt);
                    visit[xx][yy] = 1;
                }
            }
        }
    }
    return 0;
}