Brace matching in C#

sunakshi saxena

Hi

can someone help me to solve this problem.
there are some braces {{}{{}}}
How can I make a program in C# that can tell which opening brace is for which closing brace?

10 Replies

Know the answer? Post it — somebody with the same question will find it here.

Roy S15y ago
Accepted answer
using System;
using System.Collections.Generic;

namespace BraceTest
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(doBracesWork(Console.ReadLine()));
            Console.ReadLine();
        }

        static string doBracesWork(string input)
        {
            Stack openingBraces = new Stack();
            string output = "";

            for (int i = 0; i < input.Length; i++)
            {
                if (input[i] == '{')
                {
                    openingBraces.Push(i);
                }
                else if (input[i] == '}')
                {
                    output += string.Format("{0} - {1}\n", openingBraces.Pop(), i);
                }
            }

            return output;
        }
    }
}
Vulpes15y ago
Here's a neater version of the ascending or descending sequence program which avoids repeating most of the code in the for loop:

using System;

class Program
{
static void Main()
{
int[] array = {-1,-2,-3,-4,10,11,5,21,22};
int first = 0;
int last = 0;
int maxSize = 1;

for (int d = 1; d >= -1; d -=2)
{
for (int i = 0; i < array.Length ; i++)
{
int size = 1;

for (int j = i + 1; j < array.Length; j++)
{
if(array[j] - array[j-1] == d)
{
size++;
if (size > maxSize)
{
maxSize = size;
first = i;
last = j;
}
}
else
{
break;
}
}
}
}

Console.Write("The maximum number of sequential elements is {0}, namely :", maxSize);
int total = 0;
for(int i = first; i <= last; i++)
{
total += array[i];
Console.Write(" {0}", array[i]);
}

Console.WriteLine("\nTheir sum is : {0}", total);
Console.ReadKey();
}
}
Vulpes15y ago
OK, try this then:

using System;

class Program
{
static void Main()
{
int[] array = {1,2,3,4,10,11,5,21,22};
int first = 0;
int last = 0;
int maxSize = 1;

for (int i = 0; i < array.Length ; i++)
{
int size = 1;

for (int j = i + 1; j < array.Length; j++)
{
if(array[j] - array[j-1] == 1)
{
size++;
if (size > maxSize)
{
maxSize = size;
first = i;
last = j;
}
}
else
{
break;
}
}
}

Console.Write("The maximum number of sequential elements is {0}, namely :", maxSize);
int total = 0;
for(int i = first; i <= last; i++)
{
total += array[i];
Console.Write(" {0}", array[i]);
}

Console.WriteLine("\nTheir sum is : {0}", total);
Console.ReadKey();
}
}

If there's more than one sequence with the same length, then the program returns the first sequence found.

It's only looking for ascending sequences. If you want to check for descending sequences as well then insert another for loop after the first one:

for (int i = 0; i < array.Length ; i++)
{
int size = 1;

for (int j = i + 1; j < array.Length; j++)
{
if(array[j] - array[j-1] == -1)
{
size++;
if (size > maxSize)
{
maxSize = size;
first = i;
last = j;
}
}
else
{
break;
}
}
}
Deepak Kumar15y ago
thanx for your suggestion ,

but i want some more help from your side.
first i don't want to do array sort, i want the sum of sub maximum sequential array. not maximum sum of sequential array.
like if array {1,2,3,4,10,11,5,21,22}
then i want the sum of 1,2,3,4 not {21,22} maximum sum of sequential array . I want the sum of largest sub array in length .

Please provide the answer as soon as possible .

Thanx in advance .
Vulpes15y ago
A neat solution from Roy there :)

In response to your other question, try the following:

using System;

class Program
{
static void Main()
{
int[] array = {4,2,3,8,1,6,11,9,10,5};
Array.Sort(array);

int first = 0;
int last = 0;
int maxSum = array[0];

for (int i = 0; i < array.Length ; i++)
{
int sum = array[i];
if (sum > maxSum)
{
maxSum = sum;
first = i;
last = i;
}

for (int j = i + 1; j < array.Length; j++)
{
if(array[j] - array[j-1] == 1)
{
sum += array[j];
if (sum > maxSum)
{
maxSum = sum;
first = i;
last = j;
}
}
else
{
break;
}
}
}

Console.Write("The sequential numbers with the highest sum are :");
for(int i = first; i <= last; i++)
{
Console.Write(" {0}", array[i]);
}

Console.WriteLine("\nTheir sum is : {0}", maxSum);
Console.ReadKey();
}
}
sunakshi saxena15y ago
Thanks dear its working you solved my problem but i have one more question
That is suppose if i have a array like 1,2,3,4,5,6,7,8,9,10,11 than how can i get the sum of biggest sequential array from this array like if biggest sequential array from this is 8,9,10,11 hai so how can i get the sum.
sunakshi saxena15y ago
its giving error provide complete code as soon as possible
sunakshi saxena15y ago
its giving error provide complete code as soon as possible
Roy S15y ago
So a program that takes a string with braces as input and outputs the pairs of opening and closing braces? Like this?

input:
"{{}{{}}}"

output:
1 - 2
4 - 5
3 - 6
0 - 7

I would store the indices of the openingbraces in a stack and when a closing brace is found then you know that the last opening brace that was found is paired with the current closing brace.

string doBracesWork(string input)
{
    Stack openingBraces = new Stack();
    string output = "";

    for (int i = 0; i < input.Length; i++)
    {
        if (input[i] == '{')
        {
            openingBraces.Push(i);
        }
        else if (input[i] == '}')
        {
            output += string.Format("{0} - {1}\n", openingBraces.Pop(), i);
        }
    }

    return output;
}
Vilas Gite15y ago
Hi Sunakshi!

In Visual Studio, at coding part when you typed braces then its automatically highlighted for itself.