백준 3190문제

#include <bits/stdc++.h>
using namespace std;
#define x first
#define y second
#define FOR(i,a,b) for(int i=a ; i<b ; i++)

int N,K,L,sec, board[101][101];
int a,b,cur_dir;
queue<pair<int,int>> snake;

int gox[4] = {0,1,0,-1};
int goy[4] = {1,0,-1,0};

bool check(){
    return a < N && a >=0 && b < N && b >=0 && board[a][b] != 2;
}

bool move(int nxt){
    a += gox[cur_dir%4], b+= goy[cur_dir%4];
    if(!check()) return false;

    snake.push(make_pair(a,b));
    
    if(board[a][b] == 0){
        pair<int,int> tmp = snake.front();
        board[tmp.x][tmp.y] = 0;
        snake.pop();
    }
    board[a][b] = 2;

    if(nxt == 'L') cur_dir += 3;
    else if(nxt == 'D') cur_dir++;

    return true;
}

int main(){

    cin >> N >> K;
    
    FOR(i,0,K){
        int m,n; cin >> m >> n;
        board[m-1][n-1] = 1;
    }

    cin >> L;
    queue<pair<int,char>> dir;

    FOR(i,0,L){
        int s;
        char c; cin >> s >> c;
        dir.push(pair<int,char>(s,c));
    }
    pair<int,char> p = dir.front();
    dir.pop();

    cur_dir = 0;
    board[0][0] = 2;
    snake.push({0,0});

    bool flag;
    while(true){
        sec++;
        if(p.x == sec){
            flag = move((int)p.y);
            p = dir.front(), dir.pop();
        }else flag = move(0);
        if(!flag) break;
    }

    cout << sec << '\n';

    return 0;
}

백준 3190 문제 풀이입니다.