Test results - Codility

Tasks Details

easy

1. Brackets

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

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:

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 JavaScript

Time spent on task 1 minutes

Notes

not defined yet

Task timeline

Code: 07:29:37 UTC, js, verify, result: Passed

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

// 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)
     if(S.length == 0){
		        return 1;
			}
		    var startArray = new Array();
		    for(var i = 0; i < S.length; i++){
		        if(S[i] == "{" || S[i] == "[" || S[i] == "(" ){
                    startArray.push(S[i]);
				}else{
                    var str = startArray.pop();
                    if(S[i] == "}"){
                        if(str != "{"){
                            return 0;
						}
					}
                    if(S[i] == "]"){
                        if(str != "["){
                            return 0;
                        }
                    }
                    if(S[i] == ")"){
                        if(str != "("){
                            return 0;
                        }
                    }
				}
			}

			if(startArray.length > 0 ){
                return 0;
			}
			return 1;
}

Analysis

▶

example1
example test 1

✔

▶

example2
example test 2

✔

Code: 07:29:43 UTC, js, verify, result: Passed

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

// 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)
     if(S.length == 0){
		        return 1;
			}
		    var startArray = new Array();
		    for(var i = 0; i < S.length; i++){
		        if(S[i] == "{" || S[i] == "[" || S[i] == "(" ){
                    startArray.push(S[i]);
				}else{
                    var str = startArray.pop();
                    if(S[i] == "}"){
                        if(str != "{"){
                            return 0;
						}
					}
                    if(S[i] == "]"){
                        if(str != "["){
                            return 0;
                        }
                    }
                    if(S[i] == ")"){
                        if(str != "("){
                            return 0;
                        }
                    }
				}
			}

			if(startArray.length > 0 ){
                return 0;
			}
			return 1;
}

Analysis

▶

example1
example test 1

✔

▶

example2
example test 2

✔

Code: 07:29:45 UTC, js, final, score: 100

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

// 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)
     if(S.length == 0){
		        return 1;
			}
		    var startArray = new Array();
		    for(var i = 0; i < S.length; i++){
		        if(S[i] == "{" || S[i] == "[" || S[i] == "(" ){
                    startArray.push(S[i]);
				}else{
                    var str = startArray.pop();
                    if(S[i] == "}"){
                        if(str != "{"){
                            return 0;
						}
					}
                    if(S[i] == "]"){
                        if(str != "["){
                            return 0;
                        }
                    }
                    if(S[i] == ")"){
                        if(str != "("){
                            return 0;
                        }
                    }
				}
			}

			if(startArray.length > 0 ){
                return 0;
			}
			return 1;
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N)

▶

example1
example test 1

✔

▶

example2
example test 2

✔

▶

negative_match
invalid structures

✔

▶

empty
empty string

✔

▶

simple_grouped
simple grouped positive and negative test, length=22

✔

▶

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

✔

▶

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

✔

▶

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

✔

▶

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+

✔

▶

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

✔