ronith
11/1/2018 - 5:10 AM

Group the elements in k and then sort the array

Given an array of n elements and an integer k. Group the elements in k. And then sort the array.n will always be multiple of k. Ex: [1, 23, 4, 3, 8, 9] and k = 2. So number formed are 123, 43, 89. Now after sorting, it will be 43, 89, 123. Return the array as [4,3,8,9,1,23].

Group the elements in k and then sort the array.cpp
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#include <bits/stdc++.h>
using namespace std;

bool cmp (pair <string, int> a, pair <string, int> b) {
    string c= a.first, d= b.first;
    if (c.length() < d.length())
        return 1;
    else if (c.length() > d.length())
        return 0;
    else
        return c<d;
}
int main() {
    int n, k;
    cin>>n>>k;
    vector <int> a(n);
    for (int i=0;i<n;i++)
        cin>> a[i];

    vector < pair <string, int> > v;//to store the grouped elements and starting index of group.
    int i=0;
    while (i<n) {// join the numbers in groups of k elements.
        int count= 0;
        string temp= "";
        while (count<k && i<n) {
            temp+= to_string(a[i]);
            i++;
            count++;
        }
        v.push_back(make_pair(temp, i-k));
    }
    sort (v.begin(), v.end(), cmp);//sort the newly formed numbers

    vector <int> b(n);
    i=0;
    int j=0;

    while (i<v.size()) {
        int t= v[i].second, count= 0;
        while (t<n && count<k) {
            b[j]= a[t];
            t++;
            j++;
            count++;
        }
        i++;
    }
    for(int i=0;i<n;i++)
        cout<<b[i]<<" ";
}