TOI9: Pipe

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

enum dir {
    RIGHT = 0, LEFT = 1, DOWN = 2, UP = 3
};

typedef pair<int, int> pii;

const int N = 300;

pii direction[4] = {pii(0, 1), pii(0, -1), pii(1, 0), pii(-1, 0)};
int board[N + 2][N + 2];
int row, col;
bool visitedRow[N + 2][2], visitedCol[N + 2][2];

void visitedTrue(int r, int c){
    if(r == 0){
        visitedCol[c][0] = true;
    } else if(c == 0){
        visitedRow[r][0] = true;
    } else if(r == row + 1){
        visitedCol[c][1] = true;
    } else if(c == col + 1){
        visitedRow[r][1] = true;
    }
}

bool &visited(int r, int c){
    if(r == 0){
        return visitedCol[c][0];
    } else if(c == 0){
        return visitedRow[r][0];
    } else if(r == row + 1){
        return visitedCol[c][1];
    } else {
        return visitedRow[r][1];
    }
}

bool isInBoard(int r, int c){
    return r >= 0 && r <= row + 1 && c >= 0 && c <= col + 1;
}

int countPipe(int r, int c, dir d, int dist){
    visitedTrue(r, c);
    if(d == RIGHT){
        int vr = r + direction[RIGHT].first;
        int vc = c + direction[RIGHT].second;
        if(!isInBoard(vr, vc)){
            return dist;
        }
        if(board[vr][vc] == 11){
            return countPipe(vr, vc, UP, dist + 1);
        } else if(board[vr][vc] == 13){
            return countPipe(vr, vc, DOWN, dist + 1);
        } else if(board[vr][vc] == 22 || board[vr][vc] == 31){
            return countPipe(vr, vc, RIGHT, dist + 1);
        }
    } else if(d == LEFT){
        int vr = r + direction[LEFT].first;
        int vc = c + direction[LEFT].second;
        if(!isInBoard(vr, vc)){
            return dist;
        }
        if(board[vr][vc] == 12){
            return countPipe(vr, vc, UP, dist + 1);
        } else if(board[vr][vc] == 14){
            return countPipe(vr, vc, DOWN, dist + 1);
        } else if(board[vr][vc] == 22 || board[vr][vc] == 31){
            return countPipe(vr, vc, LEFT, dist + 1);
        }
    } else if(d == DOWN){
        int vr = r + direction[DOWN].first;
        int vc = c + direction[DOWN].second;
        if(!isInBoard(vr, vc)){
            return dist;
        }
        if(board[vr][vc] == 11){
            return countPipe(vr, vc, LEFT, dist + 1);
        } else if(board[vr][vc] == 12){
            return countPipe(vr, vc, RIGHT, dist + 1);
        } else if(board[vr][vc] == 21 || board[vr][vc] == 31){
            return countPipe(vr, vc, DOWN, dist + 1);
        }
    } else if(d == UP){
        int vr = r + direction[UP].first;
        int vc = c + direction[UP].second;
        if(!isInBoard(vr, vc)){
            return dist;
        }
        if(board[vr][vc] == 13){
            return countPipe(vr, vc, LEFT, dist + 1);
        } else if(board[vr][vc] == 14){
            return countPipe(vr, vc, RIGHT, dist + 1);
        } else if(board[vr][vc] == 21 || board[vr][vc] == 31){
            return countPipe(vr, vc, UP, dist + 1);
        }
    }
    return dist;
}

int main(){

    scanf("%d%d", &row, &col);
    for(int i = 1; i <= row; ++i){
        for(int j = 1; j <= col; ++j){
            scanf("%d", &board[i][j]);
        }
    }

    // Fill outline
    for(int i = 1; i <= row; ++i){
        if(board[i][1] == 11 || board[i][1] == 13 || board[i][1] == 22 || board[i][1] == 31){
            board[i][0] = 22;
        }
    }
    for(int i = 1; i <= row; ++i){
        if(board[i][col] == 12 || board[i][col] == 14 || board[i][col] == 22 || board[i][col] == 31){
            board[i][col + 1] = 22;
        }
    }
    for(int i = 1; i <= col; ++i){
        if(board[1][i] == 11 || board[1][i] == 12 || board[1][i] == 21 || board[1][i] == 31){
            board[0][i] = 21;
        }
    }
    for(int i = 1; i <= col; ++i){
        if(board[row][i] == 13 || board[row][i] == 14 || board[row][i] == 21 || board[row][i] == 31){
            board[row + 1][i] = 21;
        }
    }

    // Count Pipe
    vector<int> length;
    int cnt = 0;
    for(int i = 1; i <= col; ++i){
        if(!visited(0, i) && board[0][i] == 21){
            ++cnt;
            length.push_back(countPipe(0, i, DOWN, -1));
        }
    }
    for(int i = 1; i <= col; ++i){
        if(!visited(row + 1, i) && board[row + 1][i] == 21){
            ++cnt;
            length.push_back(countPipe(row + 1, i, UP, -1));
        }
    }
    for(int i = 1; i <= row; ++i){
        if(!visited(i, 0) && board[i][0] == 22){
            ++cnt;
            length.push_back(countPipe(i, 0, RIGHT, -1));
        }
    }
    for(int i = 1; i <= row; ++i){
        if(!visited(i, col + 1) && board[i][col + 1] == 22){
            ++cnt;
            length.push_back(countPipe(i, col + 1, LEFT, -1));
        }
    }
    cout << cnt << '\n';
    for(int x : length){
        cout << x << ' ';
    }

    return 0;
}