Solution for Exchange problem (https://cs3.interviewstreet.com/challenges/dashboard/#problem/4f846fced75d3)

Exchange.cpp

#include <iostream>
#include <algorithm>
#include <set>
#include <queue>
#include <cstring>
#include <cassert>

using namespace std;

void sccSetInsertions (set<int>& indexSet, set<int>& valSet, const int& i, const int& val)
{
    indexSet.insert (i);
    valSet.insert(val);
}

void checkSCCMembers(const int& i, const int& k, int *arr, int *swaps, queue<int>& bfsQ,
                     set<int>& sccVals, set<int>& sccIndices, int *considered)
{
    for (int j = 0; j < k; j++)
    {
        if (swaps[j] == 1)
        {
            if (considered[j] == 0)
            {
                bfsQ.push(j);
                sccSetInsertions(sccIndices, sccVals, j, arr[j]);
                considered[j] = 1;
            }           
        }
    }
}

int main (void)
{
    int k, i, j;    
    scanf ("%d", &k);   
    int arr[k];
    int swaps[k][k];
    
    for(i = 0; i < k; i++)
    {
        cin >> arr[i];
    }
    
    char c;    
    for(i = 0; i < k; i++)
    {
        for (j = 0; j < k; j++)
        {
            cin >> c;
            assert (c == 'Y' || c == 'N');
            swaps[i][j] = (c == 'Y');
        }   
    }
    
    
    set<int> sccIndices, sccVals;
    queue<int> bfsQ;        
    int considered[k], tmp;
    
    bzero (considered, sizeof(int) * k);
    
    for (i = 0; i < k; i++)
    {   
        if (considered[i] == 1)
            continue;
        else
        {
            
            sccSetInsertions(sccIndices, sccVals, i, arr[i]);
            considered[i] = 1;            
        }
        checkSCCMembers (i, k, arr, swaps[i], bfsQ, sccVals, sccIndices, considered);
        while (bfsQ.size() > 0)
        {
            tmp = bfsQ.front();
            bfsQ.pop();            
            checkSCCMembers(tmp, k, arr, swaps[tmp], bfsQ, sccVals, sccIndices, considered);
        }
        
        set<int>::iterator itVal = sccVals.begin(), itIndex = sccIndices.begin();
        for(; itIndex != sccIndices.end(); itIndex++, itVal++)
        {
            arr[*itIndex] = *itVal;        
        }
        sccIndices.clear();
        sccVals.clear();
    }
    
    for (i = 0; i < k; i++)
    {
        cout << arr[i];
        if (i != k - 1)
            cout << " ";
    }
    cout << endl;
             
    return 0;
}