Segfault task

I’m trying to solve the SEGFAULT code below, but I don’t understand how to solve this problem. Maybe someone has solved it and can help me.

#include <iostream>
#include <queue>
#include <vector>

using namespace std;

struct Position {
    int x;
    int y;
    int dist;

    Position(int _x, int _y, int _dist) : x(_x), y(_y), dist(_dist) {}
};

int captureMemory(int N, int M, vector<vector<char>>& RAM, int startX, int startY) {
    vector<vector<bool>> visited(N, vector<bool>(M, false));
    int count = 0;
    queue<Position> q;

    q.push(Position(startX, startY, 0));
    visited[startX][startY] = true;

    while (!q.empty()) {
        Position curr = q.front();
        q.pop();
        int x = curr.x;
        int y = curr.y;
        int dist = curr.dist;

        if (RAM[x][y] != '#' && RAM[x][y] != 'S') {
            RAM[x][y] = 'P';
            count++;
        }

        if (x > 0 && !visited[x - 1][y] && RAM[x - 1][y] != '#' && RAM[x - 1][y] != 'N') {
            q.push(Position(x - 1, y, dist + 1));
            visited[x - 1][y] = true;
        }
        if (x < N - 1 && !visited[x + 1][y] && RAM[x + 1][y] != '#' && RAM[x + 1][y] != 'N') {
            q.push(Position(x + 1, y, dist + 1));
            visited[x + 1][y] = true;
        }
        if (y > 0 && !visited[x][y - 1] && RAM[x][y - 1] != '#' && RAM[x][y - 1] != 'N') {
            q.push(Position(x, y - 1, dist + 1));
            visited[x][y - 1] = true;
        }
        if (y < M - 1 && !visited[x][y + 1] && RAM[x][y + 1] != '#' && RAM[x][y + 1] != 'N') {
            q.push(Position(x, y + 1, dist + 1));
            visited[x][y + 1] = true;
        }
    }

    return count;
}

int main() {
    int N, M;
    cin >> N >> M;

    vector<vector<char>> RAM(N, vector<char>(M));
    int startX, startY;

    for (int i = 0; i < N; i++) {
        string row;
        cin >> row;
        for (int j = 0; j < M; j++) {
            RAM[i][j] = row[j];
            if (RAM[i][j] == 'S') {
                startX = i;
                startY = j;
            }
        }
    }

    int K;
    cin >> K;

    vector<pair<pair<int, int>, char>> programs(K);

    for (int i = 0; i < K; i++) {
        int x, y;
        char dir;
        cin >> x >> y >> dir;
        programs[i] = make_pair(make_pair(x, y), dir);
    }

    for (const auto& program : programs) {
        int x = program.first.first;
        int y = program.first.second;
        char dir = program.second;

        while (x >= 0 && x < N && y >= 0 && y < M && RAM[x][y] != '#' && RAM[x][y] != 'S' && RAM[x][y] != 'N') {
            RAM[x][y] = 'N';
            if (dir == 'U') {
                x--;
            } else if (dir == 'D') {
                x++;
            } else if (dir == 'L') {
                y--;
            } else if (dir == 'R') {
                y++;
            }
        }
    }

    int capturedMemory = captureMemory(N, M, RAM, startX, startY);
    cout << capturedMemory << endl;

    return 0;
}