Submission #968202

#	Time	Username	Problem	Language	Result	Execution time	Memory
968202		ShauryaTheShep	Robots (APIO13_robots)	C++14	Compilation error	0 ms	0 KiB

robots

#include <iostream>
#include <queue>
#include <vector>
#include <tuple>
#include <set>
using namespace std;

const int MAX_W = 10;
const int MAX_H = 10;
const int INF = 10000;  // Large enough number to simulate "infinity"

char grid[MAX_H][MAX_W];
int w, h;

bool is_inside(int x, int y) {
    return x >= 0 && x < h && y >= 0 && y < w;
}

vector<pair<int, int>> get_moves(int x, int y) {
    vector<pair<int, int>> positions;
    // Directions: Up, Down, Left, Right
    int dx[4] = {-1, 1, 0, 0};
    int dy[4] = {0, 0, -1, 1};
    for (int d = 0; d < 4; ++d) {
        int nx = x, ny = y;
        while (is_inside(nx + dx[d], ny + dy[d]) && grid[nx + dx[d]][ny + dy[d]] != 'x') {
            nx += dx[d];
            ny += dy[d];
        }
        positions.push_back({nx, ny});
    }
    return positions;
}

int simulate(vector<int> &moves, pair<int, int> robot1, pair<int, int> robot2) {
    int move_count = 0;
    for (int move : moves) {
        pair<int, int> new_position;
        if (move < 4) {  // Moves for robot1
            new_position = get_moves(robot1.first, robot1.second)[move];
            robot1 = new_position;
        } else {  // Moves for robot2
            new_position = get_moves(robot2.first, robot2.second)[move - 4];
            robot2 = new_position;
        }

        move_count++;
        if (robot1 == robot2) {
            return move_count;
        }
    }
    return INF;
}

int brute_force(pair<int, int> robot1, pair<int, int> robot2) {
    int best = INF;
    vector<int> current_moves;
    int depth_limit = 10;  // Reasonable depth limit based on grid constraints

    // A recursive function to explore all possible move sequences up to depth_limit
    function<void(int)> explore = [&](int depth) {
        if (depth == depth_limit) {
            int result = simulate(current_moves, robot1, robot2);
            best = min(best, result);
            return;
        }

        for (int i = 0; i < 8; i++) {  // 4 directions for each robot
            current_moves.push_back(i);
            explore(depth + 1);
            current_moves.pop_back();
        }
    };

    explore(0);
    return best == INF ? -1 : best;
}

int main() {
    cin >> w >> h;
    pair<int, int> robot1, robot2;
    bool first_robot_found = false;

    for (int i = 0; i < h; ++i) {
        for (int j = 0; j < w; ++j) {
            cin >> grid[i][j];
            if (isdigit(grid[i][j])) {
                if (!first_robot_found) {
                    robot1 = {i, j};
                    first_robot_found = true;
                } else {
                    robot2 = {i, j};
                }
            }
        }
    }

    cout << brute_force(robot1, robot2) << endl;
    return 0;
}

Compilation message (stderr)

robots.cpp: In function 'int brute_force(std::pair<int, int>, std::pair<int, int>)':
robots.cpp:61:5: error: 'function' was not declared in this scope
   61 |     function<void(int)> explore = [&](int depth) {
      |     ^~~~~~~~
robots.cpp:6:1: note: 'std::function' is defined in header '<functional>'; did you forget to '#include <functional>'?
    5 | #include <set>
  +++ |+#include <functional>
    6 | using namespace std;
robots.cpp:61:14: error: expected primary-expression before 'void'
   61 |     function<void(int)> explore = [&](int depth) {
      |              ^~~~
robots.cpp:75:5: error: 'explore' was not declared in this scope
   75 |     explore(0);
      |     ^~~~~~~
robots.cpp:58:9: warning: unused variable 'depth_limit' [-Wunused-variable]
   58 |     int depth_limit = 10;  // Reasonable depth limit based on grid constraints
      |         ^~~~~~~~~~~