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 ')'.
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 6 minutes
Notes
not defined yet
Task timeline
Code: 04:41:12 UTC,
java,
autosave
Code: 04:44:11 UTC,
java,
autosave
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {}
}
}
Code: 04:44:30 UTC,
java,
autosave
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': break;
case ')': break;
}
}
}
}
Code: 04:44:52 UTC,
java,
autosave
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': case '[': case '{' break;
case ')': break;
}
}
}
}
Code: 04:45:10 UTC,
java,
autosave
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': case '{': case '[':
stack.push(c);
break;
case ')': break;
}
}
}
}
Code: 04:45:40 UTC,
java,
autosave
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': case '{': case '[':
stack.push(c);
break;
case ')':
if (stack.size() == 0 || stack.pop() != '(') {
retu
}
break;
}
}
}
}
Code: 04:45:59 UTC,
java,
autosave
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': case '{': case '[':
stack.push(c);
break;
case ')':
if (stack.size() == 0 || stack.pop() != '(') {
return 0;
}
break;
case ']':
if (stack.size() == 0 || stack.pop() != '(') {
return 0;
}
break;
case '}':
if (stack.size() == 0 || stack.pop() != '(') {
return 0;
}
break;
}
}
}
}
Code: 04:46:10 UTC,
java,
autosave
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': case '{': case '[':
stack.push(c);
break;
case ')':
if (stack.size() == 0 || stack.pop() != '(') {
return 0;
}
break;
case ']':
if (stack.size() == 0 || stack.pop() != '[') {
return 0;
}
break;
case '}':
if (stack.size() == 0 || stack.pop() != '{') {
return 0;
}
break;
}
}
}
}
Code: 04:46:21 UTC,
java,
autosave
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': case '{': case '[':
stack.push(c);
break;
case ')':
if (stack.size() == 0 || stack.pop() != '(') {
return 0;
}
break;
case '}':
if (stack.size() == 0 || stack.pop() != '{') {
return 0;
}
break;
case ']':
if (stack.size() == 0 || stack.pop() != '[') {
return 0;
}
break;
}
}
}
}
Code: 04:46:51 UTC,
java,
autosave
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': case '{': case '[':
stack.push(c);
break;
case ')':
if (stack.size() == 0 || stack.pop() != '(') {
return 0;
}
break;
case '}':
if (stack.size() == 0 || stack.pop() != '{') {
return 0;
}
break;
case ']':
if (stack.size() == 0 || stack.pop() != '[') {
return 0;
}
break;
}
}
return stack.isEmpty() ?
}
}
Code: 04:46:54 UTC,
java,
verify,
result: Passed
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': case '{': case '[':
stack.push(c);
break;
case ')':
if (stack.size() == 0 || stack.pop() != '(') {
return 0;
}
break;
case '}':
if (stack.size() == 0 || stack.pop() != '{') {
return 0;
}
break;
case ']':
if (stack.size() == 0 || stack.pop() != '[') {
return 0;
}
break;
}
}
return stack.isEmpty() ? 1 : 0;
}
}
Analysis
Code: 04:47:01 UTC,
java,
verify,
result: Passed
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': case '{': case '[':
stack.push(c);
break;
case ')':
if (stack.size() == 0 || stack.pop() != '(') {
return 0;
}
break;
case '}':
if (stack.size() == 0 || stack.pop() != '{') {
return 0;
}
break;
case ']':
if (stack.size() == 0 || stack.pop() != '[') {
return 0;
}
break;
}
}
return stack.isEmpty() ? 1 : 0;
}
}
Analysis
Code: 04:47:06 UTC,
java,
final,
score: 
100
// 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");
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> stack = new Stack<>();
for (char c : S.toCharArray()) {
switch (c) {
case '(': case '{': case '[':
stack.push(c);
break;
case ')':
if (stack.size() == 0 || stack.pop() != '(') {
return 0;
}
break;
case '}':
if (stack.size() == 0 || stack.pop() != '{') {
return 0;
}
break;
case ']':
if (stack.size() == 0 || stack.pop() != '[') {
return 0;
}
break;
}
}
return stack.isEmpty() ? 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.
0.008 s
OK
3.
0.012 s
OK
4.
0.004 s
OK
5.
0.008 s
OK
1.
0.008 s
OK
1.
0.008 s
OK
2.
0.008 s
OK
3.
0.008 s
OK
4.
0.008 s
OK
5.
0.008 s
OK
expand all
Performance tests
1.
0.228 s
OK
2.
0.008 s
OK
3.
0.024 s
OK
1.
0.032 s
OK
2.
0.008 s
OK
3.
0.012 s
OK
1.
0.200 s
OK
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+
sequence of full trees of the form T=(TT), depths [1..10..1], with/without some brackets at the end, length=49K+
✔
OK
1.
0.064 s
OK
2.
0.064 s
OK
3.
0.064 s
OK
4.
0.064 s
OK
5.
0.032 s
OK
broad_tree_with_deep_paths
string of the form [TTT...T] of 300 T's, each T being '{{{...}}}' nested 200-fold, length=120K+
string of the form [TTT...T] of 300 T's, each T being '{{{...}}}' nested 200-fold, length=120K+
✔
OK
1.
0.140 s
OK
2.
0.136 s
OK