Balanced_Brackets.java

//For a given a string expression containing only round brackets or parentheses, check if they are balanced or not. Brackets are said to be balanced if the bracket which opens last, closes first.

packageStack;
importjava.util.Stack;

publicclassBalanced_Brackets {

publicstaticbooleancheckBalanced(Stringstr) {
Stack<Character> stack = newStack<>();
for (inti = 0; i < str.length(); i++) {
charch = str.charAt(i);
if (ch == '(' || ch == '{' || ch == '[') {
stack.push(ch);
 } elseif( ch=='}' || ch==')' || ch==']' ) {

if(stack.isEmpty()) {
returnfalse;
 }
elseif(ch==')' && stack.peek()=='('||ch==']'&& stack.peek()=='['||ch=='}'&& stack.peek()=='{')
stack.pop();
else {
returnfalse;
 }
 }
 }
if(stack.isEmpty()) {
returntrue;
 }
else {
returnfalse;
 }
 }

publicstaticvoidmain(String[] args) {
Stringstring = "{ a + [ b+ (c + d)] + (e + f) }";
System.out.println(checkBalanced(string));
 }
}