Discussion on Java Stack Challenge

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9 hours ago+ 0 comments

import java.util.*; class Solution{

public static void main(String []argh)
{
    Scanner sc = new Scanner(System.in);

    String input="";
    while (sc.hasNext()) {
        input=sc.next();
        //Complete the code
        char[] charArr = input.toCharArray();
        int a=0,b=0,c=0,d=0,e=0,f=0;
        if(input.length()==0){
            System.out.println("true");
            break;
        }
        for(int i=0; i<charArr.length; i++){
            if(charArr[i]=='('){
                a+=1;
            }
            else if(charArr[i]==')'){
                b+=1;
            }
            else if(charArr[i]=='['){
                c+=1;
            }
            else if(charArr[i]==']'){
                d+=1;
            }
            else if(charArr[i]=='{'){
                e+=1;
            }
            else if(charArr[i]=='}'){
                if(e==0){
                    f-=1;
                    continue;
                }
                else{
                    f+=1;   
                }
            }
    }
    if(a==b && c==d && e==f){
        System.out.println("true");
    }
    else{
     System.out.println("false");   
    }    
    }

}

}

4 days ago+ 0 comments

	public static void main(String []argh)
	{
		Scanner sc = new Scanner(System.in);
		


        Map pairset = new HashMap<String, String>();
        pairset.put(")", "(");
        pairset.put("}", "{");
        pairset.put("]", "[");


        while (sc.hasNextLine()) {
            String input = sc.nextLine();
            // System.out.println(input);

            if (input.length() % 2 > 0) {
                System.out.println(false);

            } else {
                Stack<String> _stack = new Stack<String>();
                for (String s : input.split("")) {
                    if (_stack.size() > 0 && pairset.keySet().contains(s) && (pairset.get(s).equals(_stack.peek()))) {
                        _stack.pop();
                    } else {
                        _stack.push(s);
                    }
                }

                System.out.println((_stack.size() == 0));

            }

        }
	}

4 days ago+ 0 comments

public static void main(String []argh)
	{
		Scanner sc = new Scanner(System.in);
        Stack<Boolean> out = new Stack<Boolean>();
		Stack<String> stack = new Stack<String>();
		while (sc.hasNext()) {
			String input=sc.next();
            stack.push(input);
		}
        sc.close();
        while(!stack.isEmpty()){
            int roundParantheses = 0;
            int squareParantheses = 0;
            int curlyParantheses = 0;
            String temp = stack.pop();
            
            char[] c = temp.toCharArray();
            Stack<Character> tempStack = new Stack<Character>();
            for (char ch : c) {
                tempStack.push(ch);
            }
            
            boolean control = true;
            
            while(!tempStack.isEmpty()){
                char ch = tempStack.pop();
                if(ch == '{'){
                    if(curlyParantheses == 0){
                        control = false;
                        break;
                    }else curlyParantheses--;         
                }
                else if(ch == '['){
                    if(squareParantheses == 0){
                        control = false;
                        break;
                    }else squareParantheses--;
                }
                else if(ch == '('){
                    if(roundParantheses==0){
                        control = false;
                        break;
                    }else roundParantheses--;
                }else if(ch == '}'){
                    curlyParantheses++;
                }
                else if(ch == ']'){
                    squareParantheses++;
                }
                else if(ch == ')'){
                    roundParantheses++;
                }
            }
            
            if(control){
                if(curlyParantheses == 0 && squareParantheses == 0 && roundParantheses == 0)
                    out.push(true);
                else out.push(false);
                
            }else out.push(false);
            
        }
        
        while(!out.isEmpty()){
            System.out.println(out.pop());
        }
		
	}

1 week ago+ 1 comment

Different view

public static void main(String []argh){
		Scanner sc = new Scanner(System.in);
		while (sc.hasNext()) {
			String input=sc.next();
            //Complete the code
            while(input.contains("{}") || input.contains("()") || input.contains("[]") ){
                if(input.contains("{}")) input = input.replace("{}", "");
                if(input.contains("()")) input = input.replace("()", "");
                if(input.contains("[]")) input = input.replace("[]", ""); 
            }
        if(input.length() != 0) System.out.println("false");
        else System.out.println("true");
		}

2 weeks ago+ 0 comments

public static void main(String []argh) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            Stack<Character> stack = new Stack<>();
            String input = sc.next();
            char[] symbols = input.toCharArray();
            for (char symbol : symbols) {
                if (!stack.isEmpty()) {
                    if (symbol == '}' && stack.peek() == '{') {
                        stack.pop();
                    } else if (symbol == ')' && stack.peek() == '(') {
                        stack.pop();
                    } else if (symbol == ']' && stack.peek() == '[') {
                        stack.pop();
                    } else {
                        stack.push(symbol);
                    }
                } else {
                    stack.push(symbol);
                }
            }
            System.out.println(stack.empty());
        }
        sc.close();
    }

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