CSES - Datatähti 2025 alku

Submission details
Task:	Robotti
Sender:	rottis
Submission time:	2024-10-28 10:49:57 +0200
Language:	C++ (C++17)
Status:	READY
Result:	100

Feedback
group	verdict	score
#1	ACCEPTED	30
#2	ACCEPTED	70

Test results
test	verdict	time	group
#1	ACCEPTED	0.00 s	1, 2	details
#2	ACCEPTED	0.00 s	1, 2	details
#3	ACCEPTED	0.00 s	1, 2	details
#4	ACCEPTED	0.00 s	1, 2	details
#5	ACCEPTED	0.00 s	1, 2	details
#6	ACCEPTED	0.00 s	1, 2	details
#7	ACCEPTED	0.00 s	1, 2	details
#8	ACCEPTED	0.00 s	1, 2	details
#9	ACCEPTED	0.00 s	1, 2	details
#10	ACCEPTED	0.00 s	1, 2	details
#11	ACCEPTED	0.00 s	1, 2	details
#12	ACCEPTED	0.00 s	2	details
#13	ACCEPTED	0.00 s	2	details
#14	ACCEPTED	0.00 s	2	details
#15	ACCEPTED	0.00 s	2	details
#16	ACCEPTED	0.00 s	2	details
#17	ACCEPTED	0.01 s	2	details
#18	ACCEPTED	0.01 s	2	details
#19	ACCEPTED	0.01 s	2	details
#20	ACCEPTED	0.01 s	2	details
#21	ACCEPTED	0.01 s	2	details
#22	ACCEPTED	0.01 s	2	details
#23	ACCEPTED	0.01 s	2	details
#24	ACCEPTED	0.01 s	2	details

Compiler report

input/code.cpp: In function 'int main()':
input/code.cpp:44:27: warning: 'robot_ptr' may be used uninitialized in this function [-Wmaybe-uninitialized]
   44 |     char *right_ptr = step(board, n, robot_ptr, RIGHT);
      |                       ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Code

#define LEFT -1
#define RIGHT 1

#include <iostream>

char* step(char* board, long n, char* robot, int dir) {
    if (robot == nullptr) {
        throw "you fucked it up idiot!!!";
    }
    while (robot >= board && robot < board + n*sizeof(char)) {
        robot += dir*sizeof(char);
        if (*robot == '*') {
            return robot;
        }
    }
    return nullptr;
}

void print_board(char* board, long n) {
    for (int i = 0; i < n; i++) {
        std::cout << board[i];
    }
}

int main() {
    long n;
    std::cin >> n;
    
    char *board = (char*) malloc((1+n) * sizeof(char));

    std::cin >> board;
    
    long long steps = 0;
    long coins_collected = 0;
    
    char *robot_ptr;
    for (long i = 0; i < n; i++) {
        if (board[i] == 'R') {
            robot_ptr = board + i;
            break;
        }
    }
    char *left_ptr = step(board, n, robot_ptr, LEFT);
    char *right_ptr = step(board, n, robot_ptr, RIGHT);
    
    while (
        !(left_ptr == nullptr && right_ptr == nullptr) && (
            ( // either but not both is null
                left_ptr == nullptr || right_ptr == nullptr
            ) ||
            ( // both are not null and not in middle
                (long)(right_ptr - board) + (long)(left_ptr - board)
                != 2*(long)(robot_ptr - board)
            )
        )
        ) {
        //std::cout << (long)(left_ptr - board) << ' ' << (long)(robot_ptr - board) << ' ' << (long)(right_ptr - board) << '\n';
        // closer to left?
        if (
            (
            (robot_ptr - left_ptr < right_ptr - robot_ptr) && left_ptr != nullptr
            ) || right_ptr == nullptr
            ) {
            // go left
            steps += robot_ptr - left_ptr;
            robot_ptr = left_ptr;
            left_ptr = step(board, n, left_ptr, LEFT);
        } else {
            // go right
            steps += right_ptr - robot_ptr;
            robot_ptr = right_ptr;
            right_ptr = step(board, n, right_ptr, RIGHT);
        }
        coins_collected++;
    }
    
    std::cout << steps << ' ' << coins_collected << std::endl;
    
    return 0;
}

Test details

Test 1

Group: 1, 2

Verdict: ACCEPTED

input
`1 R` view save

correct output
`0 0` view save

user output
`0 0` view save

Test 2

Group: 1, 2

Verdict: ACCEPTED

input
`10 ...R......` view save

correct output
`0 0` view save

user output
`0 0` view save

Test 3

Group: 1, 2

Verdict: ACCEPTED

input
`10 .R...*` view save

correct output
`12 5` view save

user output
`12 5` view save

Test 4

Group: 1, 2

Verdict: ACCEPTED

input
`10 *R****` view save

correct output
`0 0` view save

user output
`0 0` view save

Test 5

Group: 1, 2

Verdict: ACCEPTED

input
`1000 R................................` view save

correct output
`947 9` view save

user output
`947 9` view save

Test 6

Group: 1, 2

Verdict: ACCEPTED

input
`1000 .................................` view save

correct output
`886 9` view save

user output
`886 9` view save

Test 7

Group: 1, 2

Verdict: ACCEPTED

input
`1000 .........................` view save

correct output
`1287 400` view save

user output
`1287 400` view save

Test 8

Group: 1, 2

Verdict: ACCEPTED

input
`1000 **********.***************...` view save

correct output
`0 0` view save

user output
`0 0` view save

Test 9

Group: 1, 2

Verdict: ACCEPTED

input
`1000 ******************************...` view save

correct output
`0 0` view save

user output
`0 0` view save

Test 10

Group: 1, 2

Verdict: ACCEPTED

input
`1000 R*****************************...` view save

correct output
`999 999` view save

user output
`999 999` view save

Test 11

Group: 1, 2

Verdict: ACCEPTED

input
`1000 ******************************...` view save

correct output
`999 999` view save

user output
`999 999` view save

Test 12

Group: 2

Verdict: ACCEPTED

input
`10000 .......*...................*...` view save

correct output
`10971 999` view save

user output
`10971 999` view save

Test 13

Group: 2

Verdict: ACCEPTED

input
`10000 ...........................` view save

correct output
`9999 999` view save

user output
`9999 999` view save

Test 14

Group: 2

Verdict: ACCEPTED

input
`10000 ...............*.....` view save

correct output
`18766 5000` view save

user output
`18766 5000` view save

Test 15

Group: 2

Verdict: ACCEPTED

input
`10000 R*****************************...` view save

correct output
`9999 9999` view save

user output
`9999 9999` view save

Test 16

Group: 2

Verdict: ACCEPTED

input
`10000 ******************************...` view save

correct output
`9999 9999` view save

user output
`9999 9999` view save

Test 17

Group: 2

Verdict: ACCEPTED

input
`200000 .................................` view save

correct output
`0 0` view save

user output
`0 0` view save

Test 18

Group: 2

Verdict: ACCEPTED

input
`200000 .................................` view save

correct output
`299934 10000` view save

user output
`299934 10000` view save

Test 19

Group: 2

Verdict: ACCEPTED

input
`200000 ............*...*....` view save

correct output
`299998 100000` view save

user output
`299998 100000` view save

Test 20

Group: 2

Verdict: ACCEPTED

input
`200000 ******************************...` view save

correct output
`0 0` view save

user output
`0 0` view save

Test 21

Group: 2

Verdict: ACCEPTED

input
`200000 R................................` view save

correct output
`133765 3` view save

user output
`133765 3` view save

Test 22

Group: 2

Verdict: ACCEPTED

input
`200000 R................................` view save

correct output
`199982 5000` view save

user output
`199982 5000` view save

Test 23

Group: 2

Verdict: ACCEPTED

input
`200000 R*****************************...` view save

correct output
`199999 199999` view save

user output
`199999 199999` view save

Test 24

Group: 2

Verdict: ACCEPTED

input
`200000 ******************************...` view save

correct output
`199999 199999` view save

user output
`199999 199999` view save

Datatähti 2025 alku

Robotti

Compiler report

Code

Test details

Test 1

Test 2

Test 3

Test 4

Test 5

Test 6

Test 7

Test 8

Test 9

Test 10

Test 11

Test 12

Test 13

Test 14

Test 15

Test 16

Test 17

Test 18

Test 19

Test 20

Test 21

Test 22

Test 23

Test 24

Tasks

Submissions (rottis)