Created
February 8, 2018 09:04
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Work out whether brackets {[()]} are balanced
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import java.util.Stack; | |
public class Main { | |
public static void main(String[] args) { | |
String s = "[]{}[][]"; | |
boolean b = isBalanced(s); | |
System.out.println(b); | |
String s2 = "[]{}[}][]"; | |
boolean b2 = isBalanced(s2); | |
System.out.println(b2); | |
String s3 = "{{})"; | |
boolean b3 = isBalanced(s3); | |
System.out.println(b3); | |
String s4 = "{{{{((]"; | |
boolean b4 = isBalanced(s4); | |
System.out.println(b4); | |
} | |
public static boolean isBalanced(String s) { | |
Stack<Character> balanceStack = new Stack<>(); | |
for(char token : s.toCharArray()) { | |
// Add Opening Tokens to a Stack | |
if( token == '{' || token == '[' || token == '(' ) { | |
balanceStack.push(token); | |
} | |
// Inspect relevant closing token | |
else if (!balanceStack.isEmpty()) { | |
char open = balanceStack.pop(); | |
// Check of mismatch between closing token | |
// and token on top of stack | |
if (token == '}') { | |
if (open != '{') { | |
return false; | |
} | |
} | |
else if (token == ']') { | |
if (open != '[') { | |
return false; | |
} | |
} | |
else if (token == ')') { | |
if (open != '(') { | |
return false; | |
} | |
} | |
} | |
} | |
return true; | |
} | |
} |
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