FilesExpand file tree

 master

/

ValidParentheses.java

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

54 lines (46 loc) · 1.34 KB

 master

/

ValidParentheses.java

Copy path

Top

File metadata and controls

• Code
• Blame

54 lines (46 loc) · 1.34 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

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

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

package stack;

import java.util.HashMap;

import java.util.Map;

import java.util.Stack;

/**

* Created by gouthamvidyapradhan on 25/02/2017. Given a string containing just the characters '(',

* ')', '{', '}', '[' and ']', determine if the input string is valid.

*

* <p>The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and

* "([)]" are not.

*/

public class ValidParentheses {

public static void main(String[] args) {

System.out.println(hasBalancedBrackets("(h[e"));

}

private static Map<Character, Character> MAP = new HashMap<>();

// METHOD SIGNATURE BEGINS, THIS METHOD IS REQUIRED

public static int hasBalancedBrackets(String str) {

if (str == null) return 1;

MAP.put(')', '(');

MAP.put('}', '{');

MAP.put('>', '<');

MAP.put(']', '[');

Stack<Character> stack = new Stack<>();

for (int i = 0, l = str.length(); i < l; i++) {

switch (str.charAt(i)) {

case '(':

case '{':

case '[':

case '<':

stack.push(str.charAt(i));

break;

case ')':

case '}':

case ']':

case '>':

if (stack.isEmpty()) return 0;

char top = stack.pop();

if (top != MAP.get(str.charAt(i))) return 0;

break;

default: // ignore

}

}

return stack.isEmpty() ? 1 : 0;

}

}