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:
class Solution { public int solution(String 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 ')'.
Copyright 2009–2024 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used Java 8
Time spent on task 2 minutes
Notes
not defined yet
Task timeline
Code: 07:28:13 UTC,
java,
autosave
Code: 07:28:23 UTC,
java,
verify,
result: Failed
// you can also use imports, for example:
// import java.util.*;
import java.util.Stack;
// 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
Stack<Character> characterStack = new Stack<Character>();
for(int i=0; i<S.length(); i++) {
if(characterStack.size() == 0) {
characterStack.push(S.charAt(i));
}else{
switch (S.charAt(i)){
case ')' :
if(characterStack.peek() == '(') characterStack.pop();
break;
default:
characterStack.push(S.charAt(i));
}
}
}
return characterStack.size()==0?0:1;
}
}
Analysis
expand all
Example tests
1.
0.004 s
WRONG ANSWER,
got 0 expected 1
1.
0.004 s
WRONG ANSWER,
got 1 expected 0
Code: 07:28:37 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
import java.util.Stack;
// 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
Stack<Character> characterStack = new Stack<Character>();
for(int i=0; i<S.length(); i++) {
if(characterStack.size() == 0) {
characterStack.push(S.charAt(i));
}else{
switch (S.charAt(i)){
case ')' :
if(characterStack.peek() == '(') characterStack.pop();
break;
default:
characterStack.push(S.charAt(i));
}
}
}
return characterStack.size()==0?1:0;
}
}
Analysis
Code: 07:28:51 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
import java.util.Stack;
// 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
Stack<Character> characterStack = new Stack<Character>();
for(int i=0; i<S.length(); i++) {
if(characterStack.size() == 0) {
characterStack.push(S.charAt(i));
}else{
switch (S.charAt(i)){
case ')' :
if(characterStack.peek() == '(') characterStack.pop();
break;
default:
characterStack.push(S.charAt(i));
}
}
}
return characterStack.size()==0?1:0;
}
}
Code: 07:29:03 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
import java.util.Stack;
// 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
Stack<Character> characterStack = new Stack<Character>();
for(int i=0; i<S.length(); i++) {
if(characterStack.size() == 0) {
characterStack.push(S.charAt(i));
}else{
switch (S.charAt(i)){
case ')' :
if(characterStack.peek() == '(') characterStack.pop();
break;
default:
characterStack.push(S.charAt(i));
}
}
}
return characterStack.size()==0?1:0;
}
}
Code: 07:29:18 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
import java.util.Stack;
// 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
Stack<Character> characterStack = new Stack<Character>();
for(int i=0; i<S.length(); i++) {
if(characterStack.size() == 0) {
characterStack.push(S.charAt(i));
}else{
switch (S.charAt(i)){
case ')' :
if(characterStack.peek() == '(') characterStack.pop();
break;
default:
characterStack.push(S.charAt(i));
}
}
}
return characterStack.size()==0?1:0;
}
}
User test case 1:
['(()(())())']
User test case 2:
['())']
User test case 3:
['(((']
User test case 4:
[')))']
User test case 5:
['()()(']
User test case 6:
[')()(']
Analysis
expand all
User tests
1.
0.004 s
OK
function result: 1
function result: 1
1.
0.004 s
OK
function result: 0
function result: 0
1.
0.004 s
OK
function result: 0
function result: 0
1.
0.008 s
OK
function result: 0
function result: 0
1.
0.008 s
OK
function result: 0
function result: 0
1.
0.004 s
OK
function result: 0
function result: 0
Code: 07:29:36 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
import java.util.Stack;
// 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
Stack<Character> characterStack = new Stack<Character>();
for(int i=0; i<S.length(); i++) {
if(characterStack.size() == 0) {
characterStack.push(S.charAt(i));
}else{
switch (S.charAt(i)){
case ')' :
if(characterStack.peek() == '(') characterStack.pop();
break;
default:
characterStack.push(S.charAt(i));
}
}
}
return characterStack.size()==0?1:0;
}
}
Code: 07:29:39 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
import java.util.Stack;
// 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
Stack<Character> characterStack = new Stack<Character>();
for(int i=0; i<S.length(); i++) {
if(characterStack.size() == 0) {
characterStack.push(S.charAt(i));
}else{
switch (S.charAt(i)){
case ')' :
if(characterStack.peek() == '(') characterStack.pop();
break;
default:
characterStack.push(S.charAt(i));
}
}
}
return characterStack.size()==0?1:0;
}
}
User test case 1:
['(()(())())']
User test case 2:
['())']
User test case 3:
['(((']
User test case 4:
[')))']
User test case 5:
['()()(']
User test case 6:
[')()(']
User test case 7:
['()']
Analysis
expand all
User tests
1.
0.008 s
OK
function result: 1
function result: 1
1.
0.008 s
OK
function result: 0
function result: 0
1.
0.008 s
OK
function result: 0
function result: 0
1.
0.008 s
OK
function result: 0
function result: 0
1.
0.008 s
OK
function result: 0
function result: 0
1.
0.012 s
OK
function result: 0
function result: 0
1.
0.008 s
OK
function result: 1
function result: 1
Code: 07:29:48 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
import java.util.Stack;
// 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
Stack<Character> characterStack = new Stack<Character>();
for(int i=0; i<S.length(); i++) {
if(characterStack.size() == 0) {
characterStack.push(S.charAt(i));
}else{
switch (S.charAt(i)){
case ')' :
if(characterStack.peek() == '(') characterStack.pop();
break;
default:
characterStack.push(S.charAt(i));
}
}
}
return characterStack.size()==0?1:0;
}
}
User test case 1:
['(()(())())']
User test case 2:
['())']
User test case 3:
['(((']
User test case 4:
[')))']
User test case 5:
['()()(']
User test case 6:
[')()(']
User test case 7:
['()']
Analysis
expand all
User tests
1.
0.004 s
OK
function result: 1
function result: 1
1.
0.004 s
OK
function result: 0
function result: 0
1.
0.004 s
OK
function result: 0
function result: 0
1.
0.004 s
OK
function result: 0
function result: 0
1.
0.004 s
OK
function result: 0
function result: 0
1.
0.004 s
OK
function result: 0
function result: 0
1.
0.004 s
OK
function result: 1
function result: 1
Code: 07:29:54 UTC,
java,
final,
score:
100
// you can also use imports, for example:
// import java.util.*;
import java.util.Stack;
// 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
Stack<Character> characterStack = new Stack<Character>();
for(int i=0; i<S.length(); i++) {
if(characterStack.size() == 0) {
characterStack.push(S.charAt(i));
}else{
switch (S.charAt(i)){
case ')' :
if(characterStack.peek() == '(') characterStack.pop();
break;
default:
characterStack.push(S.charAt(i));
}
}
}
return characterStack.size()==0?1:0;
}
}
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N)
expand all
Correctness tests
1.
0.008 s
OK
2.
0.004 s
OK
1.
0.004 s
OK
1.
0.008 s
OK
2.
0.008 s
OK
3.
0.004 s
OK
1.
0.008 s
OK
2.
0.008 s
OK
3.
0.008 s
OK
expand all
Performance tests
1.
0.036 s
OK
2.
0.036 s
OK
3.
0.004 s
OK
1.
0.272 s
OK
2.
0.008 s
OK
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+
sequence of full trees of the form T=(TT), depths [1..10..1], with/without unmatched ')' at the end, length=49K+
✔
OK
1.
0.080 s
OK
2.
0.080 s
OK
3.
0.008 s
OK
broad_tree_with_deep_paths
string of the form (TTT...T) of 300 T's, each T being '(((...)))' nested 200-fold, length=1 million
string of the form (TTT...T) of 300 T's, each T being '(((...)))' nested 200-fold, length=1 million
✔
OK
1.
1.516 s
OK
2.
0.004 s
OK