개발/알고리즘
Codility 20번 Nesting
룬아님
2019. 9. 9. 17:00
Nesting
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 consists only of the characters "(" and/or ")".
Copyright 2009–2019 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
import java.util.Stack;
class Solution {
public int solution(String S) {
Stack<Character> sstack = new Stack<Character>();
if(S.equals("")){
return 1;
}
for(int i=0; i<S.length();i++){
if(S.charAt(i)==')'){
if(sstack.empty()){
return 0;
}
if(sstack.pop() != '('){
return 0;
}
}else{
sstack.push(S.charAt(i));
}
}
if(!sstack.empty()){
return 0;
}
return 1;
}
}
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