Count pairs with given sum

Problem :

http://practice.geeksforgeeks.org/problems/count-pairs-with-given-sum/0

Solution :

	#include <iostream>
	using namespace std;
	int main()
	{
	int T;
	cin>>T;
	for(int i=0;i<T;i++)
	{
	int N,K;
	int counter=0;
	cin>>N>>K;
	int array[N];
	for(int j=0;j<N;j++)
	{
	cin>>array[j];
	}
	for(int m=0;m<N-1;m++)
	{
	for(int l=m+1;l<N;l++)
	{
	if(array[m]+array[l]==K)
	{
	counter++;
	}
	}
	}
	cout<<counter<<endl;
	}
	return 0;
	}

view raw pairs.cpp hosted with ❤ by GitHub

Matrix Transpose

Given a 2D array A, your task is to convert all rows to columns and columns to rows.
Input:
First line contains 2 space separated integers, N - total rows, M - total columns.
Each of the next N lines will contain M space separated integers.
Output:
Print M lines each containing N space separated integers.
Constraints:
$1\le N\le 10$
$1\le M\le 10$
$0\le A\left[i\right]\left[j\right]\le 100$ where $1\le i\le N$ and $1\le j\le M$

$\mathrm{Solution}$

	#include <iostream>
	using namespace std;
	int main()
	{
	int row,col;
	cin>>row>>col;
	int m[row][col];
	int mt[col][row];
	for(int i=0;i<row;i++)
	{
	for(int j=0;j<col;j++)
	{
	cin>>m[i][j];
	mt[j][i]=m[i][j];
	}
	}
	for(int k=0;k<col;k++)
	{
	for(int l=0;l<row;l++)
	{
	cout<<mt[k][l]<<" ";
	}
	cout<<endl;
	}
	return 0;
	}

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Count frequency of each element in array

Write a program to count the frequency of each element in array , as example if we have 
int a[10]={5, 10, 2, 5, 50, 5, 10, 1, 2, 2};
the output should be 
number     frequency
5          3
10         2
2          3
50         1
1          1

	#include <iostream>
	#include <cstdlib>
	using namespace std;
	int main(int argc, char** argv) {
	int a[10]={5, 10, 2, 5, 50, 5, 10, 1, 2, 2};
	int flag[10]={0};
	//count frequency of each number
	int counter=1;
	for(int i=0;i<=9;i++)
	{
	for(int j=i+1;j<=9;j++)
	{
	if (a[i]==a[j]){counter++;flag[j]=1;}
	}
	if(flag[i]!=1){cout<<a[i]<<"\t"<<counter<<endl;}
	counter=1;
	}
	return 0;
	}

view raw freq.cpp hosted with ❤ by GitHub