Problem Link: PARPER Problem - CodeChef
Feedback
Sundar K is giving really bad explanation, please choose someone else for video solution.
@sanankhan
Plzz refer my code for better understanding of the logic and implementation.
#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,k;
cin>>n>>k;
lli a[n];
lli ans=1,o=0,e=0;
for(lli i=0;i<n;i++)
{
cin>>a[i];
if(a[i]%2==0)
e++;
else
o++;
}
if(k==0)
{
if(o==0||e==0)
{
for(int i=1;i<=n;i++)
{
ans=(ans*i)%mod;
}
cout<<ans;
}
else
cout<<0;
}
else
{
if(abs(o-e)<=1)
{
if(o>e)
{
for(int i=0;i<n;i++)
{
if(i%2==0)
{
ans=(ans*o)%mod;
o--;
}
else
{
ans=(ans*e)%mod;
e--;
}
}
}
else if(e>o)
{
for(int i=0;i<n;i++)
{
if(i%2==0)
{
ans=(ans*e)%mod;
e--;
}
else
{
ans=(ans*o)%mod;
o--;
}
}
}
else
{
ans=2;
for(int i=0;i<n;i++)
{
if(i%2==0)
{
ans=(ans*e)%mod;
e--;
}
else
{
ans=(ans*o)%mod;
o--;
}
}
}
cout<<ans;
}
else
cout<<0;
}
cout<<endl;
}
}