Test results - Codility

Tasks Details

easy

1. Nesting

Determine whether a given string of parentheses (single type) is properly nested.

Task Score

100%

Correctness

100%

Performance

100%

A string S consisting of N characters is called properly nested if:

S is empty;

S has the form "(U)" where U is a properly nested string;

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

For example, string "(()(())())" is properly nested but string "())" isn't.

Write a function:

function solution(S);

that, given a string S consisting of N characters, returns 1 if string 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..1,000,000];

string S is made only of the characters '(' and/or ')'.

Solution

Programming language used JavaScript

Time spent on task 7 minutes

Notes

not defined yet

Task timeline

Code: 07:10:19 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: 07:10:20 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: 07:10:50 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    let stack = [];
    
    
}

Code: 07:11:00 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    let stack = [];
    
    while
}

Code: 07:11:23 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    let stack = [];
    
    for(let i=0; i<N; i++){
        if()
    }
}

Code: 07:11:54 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == '('){
            stack.push(S.charAt(i));
        }
    }
}

Code: 07:12:04 UTC, js, autosave

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == '('){
            stack.push(S.charAt(i));
        }
        
    }
}

Code: 07:12:17 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == '('){
            stack.push(S.charAt(i));
        }
        if(S.charAt(i) == ')'){
            
        }
    }
}

Code: 07:12:48 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == '('){
            stack.push(S.charAt(i));
        }
        if(S.charAt(i) == ')'){
            if(stack[stack.length-1] == '(')
        }
    }
}

Code: 07:13:09 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    const open
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == '('){
            stack.push(S.charAt(i));
        }
        if(S.charAt(i) == ')'){
            if(stack[stack.length-1] == '(')
        }
    }
}

Code: 07:13:35 UTC, js, autosave

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// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    const charOpen = '(';
    const charClose = ')';
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == '('){
            stack.push(S.charAt(i));
        }
        if(S.charAt(i) == ')'){
            if(stack[stack.length-1] == '(')
        }
    }
}

Code: 07:13:46 UTC, js, autosave

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    const charOpen = '(';
    const charClose = ')';
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == charOpen){
            stack.push(S.charAt(i));
        }
        if(S.charAt(i) == charClose){
            if(stack[stack.length-1] == charOpen)
        }
    }
}

Code: 07:14:06 UTC, js, autosave

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    const charOpen = '(';
    const charClose = ')';
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == charOpen){
            stack.push(S.charAt(i));
        }
        if(S.charAt(i) == charClose){
            if(stack[stack.length-1] == charOpen){
                stack.pop();
            }
            else{
                
            }
        }
    }
}

Code: 07:15:04 UTC, js, autosave

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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    const charOpen = '(';
    const charClose = ')';
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == charOpen){
            stack.push(i);
        }
        if(S.charAt(i) == charClose){
            if(stack[stack.length-1] == charOpen){
                stack.pop();
            }
            else{
                
            }
        }
    }
}

Code: 07:15:23 UTC, js, autosave

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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    const charOpen = '(';
    const charClose = ')';
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == charOpen){
            stack.push(i);
        }
        if(S.charAt(i) == charClose){
            if(stack.length > 0){
                stack.pop();
            }
            else{
                
            }
        }
    }
}

Code: 07:15:39 UTC, js, autosave

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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    const charOpen = '(';
    const charClose = ')';
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == charOpen){
            stack.push(i);
        }
        if(S.charAt(i) == charClose){
            if(stack.length > 0){
                stack.pop();
            }
            else{
                return 0;
            }
        }
    }
}

Code: 07:16:06 UTC, js, verify, result: Passed

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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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    const charOpen = '(';
    const charClose = ')';
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == charOpen){
            stack.push(i);
        }
        if(S.charAt(i) == charClose){
            if(stack.length > 0){
                stack.pop();
            }
            else{
                return 0;
            }
        }
    }
    
    if(stack.length > 0){
        return 0;
    }
    else{
        return 1;
    }
}

Analysis

expand all Example tests

▶

example1
example test

✔

0.072 s

▶

example2
example test2

✔

0.068 s

Code: 07:16:24 UTC, js, verify, result: Passed

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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    const charOpen = '(';
    const charClose = ')';
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == charOpen){
            stack.push(i);
        }
        if(S.charAt(i) == charClose){
            if(stack.length > 0){
                stack.pop();
            }
            else{
                return 0;
            }
        }
    }
    
    if(stack.length > 0){
        return 0;
    }
    else{
        return 1;
    }
}

Analysis

expand all Example tests

▶

example1
example test

✔

0.076 s

▶

example2
example test2

✔

0.072 s

Code: 07:16:27 UTC, js, 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

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(S) {
    // write your code in JavaScript (Node.js 8.9.4)
    const N = S.length;
    const charOpen = '(';
    const charClose = ')';
    let stack = [];
    
    for(let i=0; i<N; i++){
        if(S.charAt(i) == charOpen){
            stack.push(i);
        }
        if(S.charAt(i) == charClose){
            if(stack.length > 0){
                stack.pop();
            }
            else{
                return 0;
            }
        }
    }
    
    if(stack.length > 0){
        return 0;
    }
    else{
        return 1;
    }
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N)

expand all Example tests

▶

example1
example test

✔

0.072 s

▶

example2
example test2

✔

0.068 s

expand all Correctness tests

▶

negative_match
invalid structure, but the number of parentheses matches

✔

0.068 s

0.072 s

▶

empty
empty string

✔

0.068 s

▶

simple_grouped
simple grouped positive and negative test, length=22

✔

0.068 s

0.072 s

▶

small_random

✔

0.072 s

0.068 s

expand all Performance tests

▶

large1
simple large positive and negative test, 10K or 10K+1 ('s followed by 10K )'s

✔

0.076 s

0.068 s

▶

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

✔

0.080 s

0.068 s

▶

multiple_full_binary_trees
sequence of full trees of the form T=(TT), depths [1..10..1], with/without unmatched ')' at the end, length=49K+

✔

0.076 s

0.068 s

▶

broad_tree_with_deep_paths
string of the form (TTT...T) of 300 T's, each T being '(((...)))' nested 200-fold, length=1 million

✔

0.104 s

0.072 s