백준(BOJ) 2178

#include <stdio.h>
#include <queue>
 
using namespace std;
struct _pair{
    int y;
    int x;
    int cnt;
};
queue<_pair> q;
 
int R, C;
bool map[101][101];
bool visited[101][101];
int main(void){
    scanf("%d %d", &R, &C);
    getchar();
    for(int r = 0; r < R; r++){
        for(int c = 0; c < C; c++){
            map[r][c] = getchar() - '0';
        }getchar();
    }
    q.push({0, 0, 1});
    visited[0][0] = true;
    int dx[] = {1, 0, -1, 0};
    int dy[] = {0, 1, 0, -1};
    while(!q.empty()){
        _pair p = q.front();
        q.pop();
        if(p.y == R - 1 && p.x == C - 1){
            printf("%d", p.cnt);
            break;
        }
        for(int i = 0; i < 4; i++){
            int ny = p.y + dy[i];
            int nx = p.x + dx[i];
            if(ny < 0 || ny >= R || nx < 0 || nx >= C || map[ny][nx] == 0||visited[ny][nx]){
                continue;
            }
            visited[ny][nx] = true;
            q.push({ny, nx, p.cnt + 1});
 
        }
 
    }
 
 
}