Test results - Codility

Tasks Details

easy

1. Brackets

Determine whether a given string of parentheses (multiple types) is properly nested.

Task Score

Correctness

Performance

A string S consisting of N characters is considered to be properly nested if any of the following conditions is true:

S is empty;

S has the form "(U)" or "[U]" or "{U}" where U is a properly nested string;

S has the form "VW" where V and W are properly nested strings.

For example, the string "{[()()]}" is properly nested but "([)()]" is not.

Write a function:

function solution($S);

that, given a string S consisting of N characters, returns 1 if S is properly nested and 0 otherwise.

For example, given S = "{[()()]}", the function should return 1 and given S = "([)()]", the function should return 0, as explained above.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [0..200,000];

string S is made only of the following characters: '(', '{', '[', ']', '}' and/or ')'.

Solution

Programming language used PHP

Time spent on task 57 minutes

Notes

not defined yet

Code: 02:43:01 UTC, java, autosave

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// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
        // write your code in Java SE 8
    }
}

Code: 02:43:04 UTC, php, autosave

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// you can write to stdout for debugging purposes, e.g.
// print "this is a debug message\n";

function solution($S) {
    // write your code in PHP7.0
}

Code: 02:46:25 UTC, php, verify, result: Failed

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// you can write to stdout for debugging purposes, e.g.
// print "this is a debug message\n";

function solution($S) {
    return 1;
}

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.008 s

▶

example2
example test 2

✘

WRONG ANSWER
got 1 expected 0

0.008 s

WRONG ANSWER, got 1 expected 0

Code: 03:39:30 UTC, php, verify, result: Failed

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function solution($S) {
    $ans = 0;
    // rb: round bracket, sb: square bracket, br: brace
    $rb = $sb = $br = 0;
    // Split by one
    $A = str_split($S, 1);

    $N = count($A);
    if(0 != ($N % 2)) {
        return $ans;
    }

    while(($c = array_shift($A)) == true) {
        if($c = '(' && $rb == 0) { $rb++; }
        if($c = '[' && $sb == 0) { $sb++; }
        if($c = '{' && $br == 0) { $br++; }
        if($c = '}')             { $br--; }
        if($c = ']')             { $sb--; }
        if($c = ')')             { $rb--; }
    }

    if(($rb || $sb || $br) == 0) {
        $ans = 1;
    } else {
        $ans = 0;
    }

    return $ans;

}

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.004 s

▶

example2
example test 2

✘

WRONG ANSWER
got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

Code: 03:39:37 UTC, php, verify, result: Failed

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function solution($S) {
    $ans = 0;
    // rb: round bracket, sb: square bracket, br: brace
    $rb = $sb = $br = 0;
    // Split by one
    $A = str_split($S, 1);

    $N = count($A);
    if(0 != ($N % 2)) {
        return $ans;
    }

    while(($c = array_shift($A)) == true) {
        if($c = '(' && $rb == 0) { $rb++; }
        if($c = '[' && $sb == 0) { $sb++; }
        if($c = '{' && $br == 0) { $br++; }
        if($c = '}')             { $br--; }
        if($c = ']')             { $sb--; }
        if($c = ')')             { $rb--; }
    }

    if(($rb || $sb || $br) == 0) {
        $ans = 1;
    } else {
        $ans = 0;
    }

    return $ans;

}

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.004 s

▶

example2
example test 2

✘

WRONG ANSWER
got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

Code: 03:39:40 UTC, php, final, score: 0

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function solution($S) {
    $ans = 0;
    // rb: round bracket, sb: square bracket, br: brace
    $rb = $sb = $br = 0;
    // Split by one
    $A = str_split($S, 1);

    $N = count($A);
    if(0 != ($N % 2)) {
        return $ans;
    }

    while(($c = array_shift($A)) == true) {
        if($c = '(' && $rb == 0) { $rb++; }
        if($c = '[' && $sb == 0) { $sb++; }
        if($c = '{' && $br == 0) { $br++; }
        if($c = '}')             { $br--; }
        if($c = ']')             { $sb--; }
        if($c = ')')             { $rb--; }
    }

    if(($rb || $sb || $br) == 0) {
        $ans = 1;
    } else {
        $ans = 0;
    }

    return $ans;

}

Analysis summary

The following issues have been detected: wrong answers, timeout errors.

For example, for the input '([)()]' the solution returned a wrong answer (got 1 expected 0).

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.004 s

▶

example2
example test 2

✘

WRONG ANSWER
got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

expand all Correctness tests

▶

negative_match
invalid structures

✘

WRONG ANSWER
got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

▶

empty
empty string

✘

WRONG ANSWER
got 0 expected 1

0.004 s

WRONG ANSWER, got 0 expected 1

▶

simple_grouped
simple grouped positive and negative test, length=22

✘

WRONG ANSWER
got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

0.004 s

expand all Performance tests

▶

large1
simple large positive test, 100K ('s followed by 100K )'s + )(

✘

TIMEOUT ERROR
running time: >6.00 sec., time limit: 0.14 sec.

6.000 s

TIMEOUT ERROR, running time: >6.00 sec., time limit: 0.14 sec.

0.004 s

WRONG ANSWER, got 1 expected 0

0.288 s

TIMEOUT ERROR, running time: 0.29 sec., time limit: 0.10 sec.

▶

large2
simple large negative test, 10K+1 ('s followed by 10K )'s + )( + ()

✘

WRONG ANSWER
got 1 expected 0

0.004 s

WRONG ANSWER, got 1 expected 0

0.004 s

▶

large_full_ternary_tree
tree of the form T=(TTT) and depth 11, length=177K+

✘

TIMEOUT ERROR
running time: >6.00 sec., time limit: 0.13 sec.

6.000 s

TIMEOUT ERROR, running time: >6.00 sec., time limit: 0.13 sec.

▶

multiple_full_binary_trees
sequence of full trees of the form T=(TT), depths [1..10..1], with/without some brackets at the end, length=49K+

✘

TIMEOUT ERROR
running time: 3.50 sec., time limit: 0.10 sec.

3.504 s

TIMEOUT ERROR, running time: 3.50 sec., time limit: 0.10 sec.

0.008 s

3.504 s

TIMEOUT ERROR, running time: 3.50 sec., time limit: 0.10 sec.

3.548 s

TIMEOUT ERROR, running time: 3.55 sec., time limit: 0.10 sec.

3.516 s

TIMEOUT ERROR, running time: 3.52 sec., time limit: 0.10 sec.

▶

broad_tree_with_deep_paths
string of the form [TTT...T] of 300 T's, each T being '{{{...}}}' nested 200-fold, length=120K+

✘

TIMEOUT ERROR
running time: >6.00 sec., time limit: 0.11 sec.

6.000 s

TIMEOUT ERROR, running time: >6.00 sec., time limit: 0.11 sec.

6.000 s

TIMEOUT ERROR, running time: >6.00 sec., time limit: 0.11 sec.