Robotti

input/code.cpp: In function 'void solve()':
input/code.cpp:15:10: warning: unused variable 't' [-Wunused-variable]
   15 |     char t;
      |          ^

#include<bits/stdc++.h>
using namespace std;

#define int long long
#define debug(x) cout << #x << ": " << (x) << " | "
#define Debug(x) cout << #x << ": " << (x) << "\n"

const int M = 22;
char grid[M][M];

void solve() {
    int n;
    cin >> n;

    char t;
    for (int i=0; i<n; i++) {
        for (int j=0; j<n; j++) {
            cin >> grid[j][i];
        }
    }

    int dx=0, dy=1, tmp;
    int posx=0, posy=-1;
    for (int ans =0; ans<1000010; ans++) {
        //debug(posx); debug(posy); debug(dx); Debug(dy);

        posx+= dx;
        posy+= dy;
        if (posx<0 || posx>=n || posy<0 || posy>=n) {
            cout << ans << "\n";
            return;
        }
        if (grid[posx][posy] == '.') continue;
        if (grid[posx][posy] == '/') {
            tmp = -dx;
            dx = -dy;
            dy = tmp;

            grid[posx][posy] = '\\';
        }
        else if (grid[posx][posy] == '\\') {
            tmp = dx;
            dx = dy;
            dy = tmp;

            grid[posx][posy] = '/';
        }
    }
}

signed main() {
    cin.tie(0) -> ios::sync_with_stdio(0);
    solve();
}

Test 1 (public)

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED