CareerCup

public static boolean isWellFormed(String input)
	{
		if(input==null) return true;
		if(input.length()==0) return true;
		
		Stack<Character> stack = new Stack<Character>();
		for(int i=0; i<input.length(); ++i)
		{
			char temp = input.charAt(i);
						
			if(temp =='[' || temp =='{' || temp =='(' ) 
				stack.push(temp);
			
			if(temp ==']' || temp == '}' || temp == ')') 
			{
				if(stack.isEmpty()) return false;
				if(temp != stack.pop()) return false;
			}
		}
		if(!stack.isEmpty()) return false;
		return true;
	}

what is string id [}{)(]

Using the above code with stack fails for the input [}{)(]

I have tried the classic way. Let me know, if you see any bugs.

public static bool isWellFormed(String input)
{
if (input == null) return true;
if (input.Length == 0) return true;

int count = 0;
for (int i = 0; i < input.Length; i++)
{
char iChar=input[i];
if (iChar == '(' || iChar == '{' || iChar == '[')
count++;

if (input[i] == ')' || iChar == '}' || iChar == ']')
count--;
}
return ((count==0)?true:false);
}

@kumar
The question is to check for wellformed and not to count whether the number of opening and closing brackets match. You code does not do even the basic.

<pre lang="" line="1" title="CodeMonkey59664" class="run-this">import java.util.HashMap;
import java.util.Map;
import java.util.Stack;


public class WellFormedString {
static Map<Character, Character> map = new HashMap<Character, Character>();

static {
map.put(']', '[');
map.put('}', '{');
map.put(')', '(');
}

public static void main(String[] args) {
System.out.println(isWellFormed("(}"));
}

public static boolean isWellFormed(String input) {

if (input == null)
return true;

if (input.length() == 0)
return true;

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

for (int i = 0; i < input.length(); ++i) {
char temp = input.charAt(i);

if ((temp == '[') || (temp == '{') || (temp == '('))
stack.push(temp);

if ((temp == ']') || (temp == '}') || (temp == ')')) {

if (stack.isEmpty())
return false;

if (map.get(temp) != stack.pop())
return false;
}
}

if (!stack.isEmpty())
return false;

return true;
}
}

</pre><pre title="CodeMonkey59664" input="yes">
</pre>

import java.util.*;
public class wellFormed
{
public static void main(String []args)
{
String str="[[{]{(())}}]]";
if(isBalanced(str))
        System.out.println("balanced");
else
        System.out.println("not balanced");
}

public static boolean isBalanced(String str)
{
Stack<Character> s=new Stack<Character>();
for(int i=0;i<str.length();++i)
{
        if(str.charAt(i)=='{' || str.charAt(i)=='(' || str.charAt(i)=='[')
                s.push(str.charAt(i));
        if(str.charAt(i)=='}' || str.charAt(i)==')' || str.charAt(i)==']')
                if(!matchParenthesis(s.pop(),str.charAt(i)))
                        return false;
}
if(!s.isEmpty())
        return false;
return true;
}
public static boolean matchParenthesis(char a,char b)
{
        if((a=='{' && b=='}') || (a=='(' && b==')') || (a=='[' && b==']'))
                return true;
        else
                return false;
}
}

(()(()))

public bool iswellformed(string str)
    {
        Stack<char> s = new Stack<char>();
        if (str.Length == 0)
            return false;
        for (int i = 0; i < str.Length; i++)
        {

                if ((str[i]=='{') || (str[i]=='[') || (str[i]=='('))
            {
                s.Push(str[i]); 
            }
                else if ((str[i] == '}') || (str[i] == ']') || (str[i] == ')'))
            {
                if (s.Count == 0)
                    return false;
                char pop = s.Pop();
                if ((str[i] != '}' && pop=='{') || ((str[i] != ']') && pop =='[') || ((str[i] != ')')&& pop=='('))
                    return false;
            }
        }
        if (s.Count != 0)
            return false;

        return true;
    }

Hi Bru,


Such vivid info on the
Amazon Interview Question for Software Engineer in Tests ! Flabbergasted! Thank you for making the read a smooth sail!




The Make Public function in S3 is perfectly working these past few months and years I should say.
Just last week, we are experiencing failure in the "Make Public" function. Once I successfully upload a folder with multiple files) then Make Public the uploaded files, the notification below shows Failure

Anyways great write up, your efforts are much appreciated.


MuchasGracias,
Morgan