From 771ba7f813625e8a15bcc4045f956e96d6bfec54 Mon Sep 17 00:00:00 2001
From: ShazidMahsrafi <shazid456@gmail.com>
Date: Tue, 25 Jun 2024 04:30:45 +0600
Subject: [PATCH] feat: Add solution for Codeforces problem 1986E

---
 Codes/1986 E - Beautiful Array/1986E.cpp | 84 ++++++++++++++++++++++++
 Readme.md                                |  1 +
 2 files changed, 85 insertions(+)
 create mode 100644 Codes/1986 E - Beautiful Array/1986E.cpp

diff --git a/Codes/1986 E - Beautiful Array/1986E.cpp b/Codes/1986 E - Beautiful Array/1986E.cpp
new file mode 100644
index 0000000..f0d6347
--- /dev/null
+++ b/Codes/1986 E - Beautiful Array/1986E.cpp	
@@ -0,0 +1,84 @@
+#include <bits/stdc++.h>
+using namespace std;
+#ifdef ONLINE_JUDGE
+#define dbg(...)
+#else
+#include "Assets/debug.h"
+#endif
+#define int long long
+#define ll long long
+#define endl '\n'
+#define all(x) x.begin(), x.end()
+#define sz(x) (int)(x).size()
+#define yes cout << "YES" << endl
+#define no cout << "NO" << endl
+#define rep(i,a,b)  for(int i=a; i<b; ++i)
+#define rrep(i,a,b) for(int i=a; i>=b; --i)
+#define pb push_back
+#define ppb pop_back
+#define ins insert
+#define ff first
+#define ss  second
+#define FAST (ios_base::sync_with_stdio(false), cin.tie(nullptr));
+ll pow(ll x,ll y,ll m=1e9+7){ll ans=1;x%=m;while(y){if(y&1)ans=(ans*x)%m;x=(x*x)%m;y>>=1;}return ans;}
+
+void solve()
+{
+    int n,k;
+    cin>>n>>k;
+    map<int,vector<int>>m;
+    rep(i,0,n)
+    {
+        int x;
+        cin>>x;
+        m[x%k].pb(x/k);
+    }
+    int odd=n&1, ans=0;
+    for(auto it:m)
+    {
+        vector<int>&v=it.second;
+        int len = sz(v);
+        sort(all(v));
+        if(len&1)
+        {
+            if(!odd)
+            {
+                cout<<-1<<endl;
+                return;
+            }
+            odd--;
+            if(len==1)  continue;
+            vector<int>pf(len,0),sf(len,0);
+            pf[1]=v[1]-v[0];
+            sf[len-2]=v[len-1]-v[len-2];
+            for(int i=3; i<len; i+=2)   pf[i]=pf[i-2]+v[i]-v[i-1];
+            for(int i=len-4; i>=0; i-=2)    sf[i]=sf[i+2]+v[i+1]-v[i];
+            int mn=INT_MAX;
+            for(int i=0; i<len; i+=2)
+            {
+                int sum=0;
+                if(i>0) sum+=pf[i-1];
+                if(i<len-1)  sum+=sf[i+1];
+                mn = min(mn,sum);
+            }
+            ans+=mn;
+        }
+        else
+        {
+            for(int i=1; i<len; i+=2)   ans+=v[i]-v[i-1];
+        }
+    }
+    cout<<ans<<endl;   
+}
+
+signed main()
+{
+    FAST;
+    int TCS = 1;
+    cin >> TCS;
+    for (int TC = 1; TC <= TCS; ++TC)
+    {
+      // cout<<"Case "<<TC<<": ";
+      solve();
+    }
+}
\ No newline at end of file
diff --git a/Readme.md b/Readme.md
index 023f80f..37bf31f 100644
--- a/Readme.md
+++ b/Readme.md
@@ -353,6 +353,7 @@ This repository contains my solutions of Codeforces problems. They are in C++ la
 | 341 | 1986 B | Matrix Stabilization | [Question](https://codeforces.com/problemset/problem/1986/B) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1986%20B%20-%20Matrix%20Stabilization)
 | 342 | 1986 C | Update Queries | [Question](https://codeforces.com/problemset/problem/1986/C) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1986%20C%20-%20Update%20Queries)
 | 343 | 1986 D | Mathematical Problem | [Question](https://codeforces.com/problemset/problem/1986/D) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1986%20D%20-%20Mathematical%20Problem)
+| 344 | 1986 E | Beautiful Array | [Question](https://codeforces.com/problemset/problem/1986/E) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1986%20E%20-%20Beautiful%20Array)