My issue
Array B consist of N pair.say pair(sum,diff)
If Array A possible .sum=x+y,diff=|x-y|where x and y belongs to A.if sum even->diff even.if sum odd ->diff(odd).create two arr odd and even if both are of even size then Array A possible.sort the both arr in descending order such that sum belong to left half and diff belong to right half.
For test case 3 5 4 4 it is printed 4 4 1 1.but correct o/p is 4 4 0 1
My code
#include <iostream>
#include<bits/stdc++.h>
using namespace std;
int main() {
int t;cin>>t;
while(t--){
int n;cin>>n;
vector<int>e,o,a(n);
for(int i=0;i<n;i++){
int x;
cin>>x;
x&1?o.push_back(x):e.push_back(x);
}
if(o.size()%2>0||e.size()%2>0){
cout<<-1<<endl;
continue;
}
sort(e.begin(),e.end(),greater<int>());
sort(o.begin(),o.end(),greater<int>());
int eSize=e.size(),oSize=o.size();
int j=0;
for(int i=0;i<eSize/2;i++){
int x=(e[i]+e[i+(eSize/2)])/2;
int y=(e[i]-e[i+(eSize/2)])/2;
a[j]=x;
a[j+n/2]=y;
j++;
}
for(int i=0;i<oSize;i++){
int x=(o[i]+o[i+(oSize/2)])/2;
int y=(o[i]-o[i+(oSize/2)])/2;
a[j]=x;
a[j+n/2]=y;
j++;
}
for(auto u:a)
cout<<u<<" ";
cout<<endl;
}
return 0;
}
Problem Link: Alter Ego Practice Coding Problem - CodeChef
@nadiyasoaib
i think u have made some mistake in implementation part
here refer my c++ code to debug it.
but your logic seems correct .
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#include<algorithm>
#include<numeric>
using namespace std;
typedef long long int lli;
using namespace __gnu_pbds;
template<class T> using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
//typedef long long int lli;
//typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> multi_pbds;
//typedef tree<pair<int , int>, null_type, less<pair<int ,int>>, rb_tree_tag, tree_order_statistics_node_update> pbdsp;
//typedef tree< int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
#define nl "\n";
#define fastio ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define db long double
#define prq priority_queue<lli>
#define psq priority_queue<lli,vector<lli>,greater<lli>>
#define mod 1000000007
#define lb lower_bound
#define ub upper_bound
#define vlli vector<lli>
#define mslli multiset<lli>
#define inf 1e17
#define sp " "
#define pb push_back
#define pie 3.14159265358979323846
#define test lli t; cin>>t; while(t--)
int32_t main()
{
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
test{
lli n;
cin>>n;
lli a[n];
vector<lli> o,e;
lli cnt=0;
for(lli i=0;i<n;i++)
{
cin>>a[i];
if(a[i]%2)
cnt++;
if(a[i]%2)
o.push_back(a[i]);
else
e.push_back(a[i]);
}
if(cnt%2)
cout<<-1;
else
{
sort(e.begin(),e.end());
sort(o.begin(),o.end());
int k=0;
lli ans[n];
for(int i=0,j=o.size()-1;i<j;i++,j--)
{
lli val=(o[i]+o[j])/2;
ans[k]=val;
ans[k+(n/2)]=val-o[i];
k++;
}
for(int i=0,j=e.size()-1;i<j;i++,j--)
{
lli val=(e[i]+e[j])/2;
ans[k]=val;
ans[k+(n/2)]=val-e[i];
k++;
}
for(int i=0;i<n;i++)
cout<<ans[i]<<" ";
}
cout<<endl;
}
}
1 Like