CSES - Datatähti 2025 alku - Results
Submission details
Task:Robotti
Sender:osmukka
Submission time:2024-11-06 10:30:25 +0200
Language:C
Status:COMPILE ERROR

Compiler report

input/code.c: In function 'main':
input/code.c:42:11: warning: implicit declaration of function 'read'; did you mean 'fread'? [-Wimplicit-function-declaration]
   42 |     while(read(STDIN_FILENO, &ch, 1) > 0)
      |           ^~~~
      |           fread
input/code.c:42:16: error: 'STDIN_FILENO' undeclared (first use in this function)
   42 |     while(read(STDIN_FILENO, &ch, 1) > 0)
      |                ^~~~~~~~~~~~
input/code.c:42:16: note: each undeclared identifier is reported only once for each function it appears in
input/code.c:55:11: error: expected expression before ')' token
   55 |     while()
      |           ^
input/code.c:57:20: error: 'i' undeclared (first use in this function)
   57 |     for(int i = 0; i < amount; i++)
      |                    ^
input/code.c:103:9: error: expected expression before ':' token
  103 |     std::cout << steps << " " << coins << "\n";
      |         ^
input/code.c:103:5: warning: label 'std' defined but not used [-Wunused-label]
  1...

Code

#include <stdio.h>
#include <stdlib.h>
#include <string.h>


int distance_left(char* array, int robot_index)
{

    for(int i = robot_index-1; i >= 0; i--)
    {
        if(array[i] == '*')
        {
            return robot_index - i;
        }
    }
    // If no coins exist to the left. Distance between two indices can't be -1.
    return -1;
}


int distance_right(char* array, int robot_index, const int array_len)
{
    for(int i = array_len-robot_index; i <= array_len; i--)
    {
        if(array[i] == '*')
        {
            return i - robot_index;
        }
    }
    // Distance cant be negative.
    return -1;
}


int main()
{
    char ch;
    int number_index = 0;
    char amount_str[7] = {0, 0, 0, 0, 0, 0, 0};
    int amount = 0;

    while(read(STDIN_FILENO, &ch, 1) > 0)
    {
        amount_str[number_index] = ch;
    }
    amount = atoi(amount_str);

    char* rooms = malloc(sizeof(char)*amount);
    read(STDIN_FILENO, &rooms, 1);

    int robot_index = 0;
    int steps = 0;
    int coins = 0;
 
    while()

    for(int i = 0; i < amount; i++)
    {
        if(rooms[i] == 'R')
        {
            robot_index = i;
            break;
        }
    }

    int d_left  = distance_left(rooms, robot_index);
    int d_right = distance_right(rooms, robot_index, amount);

    while(1)
    {
        //if(d_left == 0)
            d_left = distance_left(rooms, robot_index);
        //else if(d_right == 0)
            d_right = distance_right(rooms, robot_index, amount);

        if(d_left < d_right)
        {
            rooms[robot_index] = '.';
            robot_index--;
            rooms[robot_index] = 'R';
            steps += d_left;

            d_right += d_left;
            coins++;
            d_left = 0;
        }
        else if(d_right < d_left)
        {
            rooms[robot_index] = '.';
            robot_index++;
            rooms[robot_index] = 'R';

            steps += d_right;
            coins++;
            d_right = 0;
        }
        else
        {
            break;
        }
    }
 
    std::cout << steps << " " << coins << "\n";
    return 0;
}