Test results - Codility

Tasks Details

easy

1. Brackets

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

Task Score

100%

Correctness

100%

Performance

100%

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:

class Solution { public int solution(string 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 C#

Time spent on task 4 minutes

Notes

not defined yet

Code: 09:14:19 UTC, cs, verify, result: Failed

show code in pop-up

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using System;
using System.Linq;

class Solution {
    public int solution(string S) {
        
        // Console.WriteLine("S : " + S);
        
        S = S.Replace('(','2');
        S = S.Replace(')','3');
        S = S.Replace('[','4');
        S = S.Replace(']','5');
        S = S.Replace('{','6');
        S = S.Replace('}','7');
        int[] s = S.Select(a => a - '0').ToArray();
        
        int N = s.Length;
        int result = 0;
        
        for(int i = 1; i < 4; i++)
        {
            int tgt = i * 2;
            // Console.WriteLine("tgt : " + tgt);

            for(int j = 0; j < N; j++)
            {
                // Console.WriteLine("s[j] : " + s[j]);
                // Console.WriteLine("result : " + result);
                if(s[j] == 0) continue;
                
                if(s[j] == tgt) 
                {
                    result += 1;
                    s[j] = 0;
                }
                else if(s[j] == (tgt + 1)) 
                {
                    result -= 1;
                    if(result < 0) return 0;
                    s[j] = 0;
                }
                // else if(result != 0) return 0;
            }
            
            if(result != 0) return 0;
        }
        
        return 1;
    }
}

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.057 s

▶

example2
example test 2

✘

WRONG ANSWER
got 1 expected 0

0.057 s

WRONG ANSWER, got 1 expected 0

Code: 09:14:57 UTC, cs, verify, result: Passed

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using System;
using System.Linq;

class Solution {
    public int solution(string S) {
        
        // Console.WriteLine("S : " + S);
        
        S = S.Replace('(','2');
        S = S.Replace(')','3');
        S = S.Replace('[','4');
        S = S.Replace(']','5');
        S = S.Replace('{','6');
        S = S.Replace('}','7');
        int[] s = S.Select(a => a - '0').ToArray();
        
        int N = s.Length;
        int result = 0;
        
        for(int i = 0; i < N; i++)
        {
            if(s[i] % 2 == 0 && i + 1 < N && s[i + 1] % 2 == 1 && s[i + 1] != (s[i] + 1)) return 0;
        }
        
        for(int i = 1; i < 4; i++)
        {
            int tgt = i * 2;
            // Console.WriteLine("tgt : " + tgt);

            for(int j = 0; j < N; j++)
            {
                // Console.WriteLine("s[j] : " + s[j]);
                // Console.WriteLine("result : " + result);
                if(s[j] == 0) continue;
                
                if(s[j] == tgt) 
                {
                    result += 1;
                    s[j] = 0;
                }
                else if(s[j] == (tgt + 1)) 
                {
                    result -= 1;
                    if(result < 0) return 0;
                    s[j] = 0;
                }
                // else if(result < 0) return 0;
            }
            
            if(result != 0) return 0;
        }
        
        return 1;
    }
}

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.037 s

▶

example2
example test 2

✔

0.038 s

Code: 09:15:51 UTC, cs, verify, result: Passed

show code in pop-up

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using System;
using System.Linq;

class Solution {
    public int solution(string S) {
        
        // Console.WriteLine("S : " + S);
        
        S = S.Replace('(','2');
        S = S.Replace(')','3');
        S = S.Replace('[','4');
        S = S.Replace(']','5');
        S = S.Replace('{','6');
        S = S.Replace('}','7');
        int[] s = S.Select(a => a - '0').ToArray();
        
        int N = s.Length;
        int result = 0;
        
        for(int i = 0; i < N; i++)
        {
            if(s[i] % 2 == 0 && i + 1 < N && s[i + 1] % 2 == 1 && s[i + 1] != (s[i] + 1)) return 0;
        }
        
        for(int i = 1; i < 4; i++)
        {
            int tgt = i * 2;
            // Console.WriteLine("tgt : " + tgt);

            for(int j = 0; j < N; j++)
            {
                // Console.WriteLine("s[j] : " + s[j]);
                // Console.WriteLine("result : " + result);
                if(s[j] == 0) continue;
                
                if(s[j] == tgt) 
                {
                    result += 1;
                    s[j] = 0;
                }
                else if(s[j] == (tgt + 1)) 
                {
                    result -= 1;
                    if(result < 0) return 0;
                    s[j] = 0;
                }
            }
            if(result != 0) return 0;
        }
        
        return 1;
    }
}

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.060 s

▶

example2
example test 2

✔

0.058 s

Code: 09:15:58 UTC, cs, verify, result: Passed

show code in pop-up

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using System;
using System.Linq;

class Solution {
    public int solution(string S) {
        
        // Console.WriteLine("S : " + S);
        
        S = S.Replace('(','2');
        S = S.Replace(')','3');
        S = S.Replace('[','4');
        S = S.Replace(']','5');
        S = S.Replace('{','6');
        S = S.Replace('}','7');
        int[] s = S.Select(a => a - '0').ToArray();
        
        int N = s.Length;
        int result = 0;
        
        for(int i = 0; i < N; i++)
        {
            if(s[i] % 2 == 0 && i + 1 < N && s[i + 1] % 2 == 1 && s[i + 1] != (s[i] + 1)) return 0;
        }
        
        for(int i = 1; i < 4; i++)
        {
            int tgt = i * 2;
            // Console.WriteLine("tgt : " + tgt);

            for(int j = 0; j < N; j++)
            {
                // Console.WriteLine("s[j] : " + s[j]);
                // Console.WriteLine("result : " + result);
                if(s[j] == 0) continue;
                
                if(s[j] == tgt) 
                {
                    result += 1;
                    s[j] = 0;
                }
                else if(s[j] == (tgt + 1)) 
                {
                    result -= 1;
                    if(result < 0) return 0;
                    s[j] = 0;
                }
            }
            if(result != 0) return 0;
        }
        
        return 1;
    }
}

Analysis

expand all Example tests

▶

example1
example test 1

✔

0.058 s

▶

example2
example test 2

✔

0.060 s

Code: 09:16:01 UTC, cs, final, score: 100

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

using System;
using System.Linq;

class Solution {
    public int solution(string S) {
        
        // Console.WriteLine("S : " + S);
        
        S = S.Replace('(','2');
        S = S.Replace(')','3');
        S = S.Replace('[','4');
        S = S.Replace(']','5');
        S = S.Replace('{','6');
        S = S.Replace('}','7');
        int[] s = S.Select(a => a - '0').ToArray();
        
        int N = s.Length;
        int result = 0;
        
        for(int i = 0; i < N; i++)
        {
            if(s[i] % 2 == 0 && i + 1 < N && s[i + 1] % 2 == 1 && s[i + 1] != (s[i] + 1)) return 0;
        }
        
        for(int i = 1; i < 4; i++)
        {
            int tgt = i * 2;
            // Console.WriteLine("tgt : " + tgt);

            for(int j = 0; j < N; j++)
            {
                // Console.WriteLine("s[j] : " + s[j]);
                // Console.WriteLine("result : " + result);
                if(s[j] == 0) continue;
                
                if(s[j] == tgt) 
                {
                    result += 1;
                    s[j] = 0;
                }
                else if(s[j] == (tgt + 1)) 
                {
                    result -= 1;
                    if(result < 0) return 0;
                    s[j] = 0;
                }
            }
            if(result != 0) return 0;
        }
        
        return 1;
    }
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N)

expand all Example tests

▶

example1
example test 1

✔

0.060 s

▶

example2
example test 2

✔

0.060 s

expand all Correctness tests

▶

negative_match
invalid structures

✔

0.057 s

0.058 s

▶

empty
empty string

✔

0.059 s

▶

simple_grouped
simple grouped positive and negative test, length=22

✔

0.058 s

0.057 s

0.058 s

0.060 s

0.058 s

expand all Performance tests

▶

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

✔

0.076 s

0.058 s

▶

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

✔

0.060 s

0.057 s

0.059 s

▶

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

✔

0.074 s

▶

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+

✔

0.064 s

0.065 s

0.061 s

0.062 s

0.065 s

▶

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

✔

0.072 s

0.067 s