From 09ad1c83dfa3645ec6ce2a15f614ae65856e5f54 Mon Sep 17 00:00:00 2001
From: ShazidMahsrafi <shazid456@gmail.com>
Date: Wed, 4 Sep 2024 00:59:16 +0600
Subject: [PATCH] feat: Add solution for Codeforces problem 2009 D - Satyam and
 Counting

---
 Codes/2009 D - Satyam and Counting/2009D.cpp | 67 ++++++++++++++++++++
 Readme.md                                    |  1 +
 2 files changed, 68 insertions(+)
 create mode 100644 Codes/2009 D - Satyam and Counting/2009D.cpp

diff --git a/Codes/2009 D - Satyam and Counting/2009D.cpp b/Codes/2009 D - Satyam and Counting/2009D.cpp
new file mode 100644
index 0000000..e54083a
--- /dev/null
+++ b/Codes/2009 D - Satyam and Counting/2009D.cpp	
@@ -0,0 +1,67 @@
+#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  ff  first
+#define  ss  second
+#define  ins  insert
+#define  pb  push_back
+#define  ppb  pop_back
+#define  sz(x)  (int)(x).size()
+#define  all(x)  x.begin(), x.end()
+#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  yn(f)  f? cout<<"YES\n":cout<<"NO\n"
+#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;
+    cin>>n;
+    vector<bool>one(n+10,false),zero(n+10,false);
+    int ct_one=0, ct_zero=0;
+    rep(i,0,n)
+    {
+        int x,y;
+        cin>>x>>y;
+        if(y) 
+        {
+            one[x]=1;
+            ct_one++;
+        }
+        else 
+        {
+            zero[x]=1;
+            ct_zero++;
+        }
+    }
+    dbg(one,zero);
+    dbg(ct_one, ct_zero);
+    int ans=0;
+    rep(i,0,n)
+    {
+        if(one[i] && zero[i])  ans += ct_one+ct_zero-2;
+        if(one[i] && zero[i+1] && one[i+2])     ans++;
+        if(zero[i] && one[i+1] && zero[i+2])    ans++; 
+    }
+    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 18d0067..7ac0c0d 100644
--- a/Readme.md
+++ b/Readme.md
@@ -407,6 +407,7 @@ This repository contains my solutions of Codeforces problems. They are in C++ la
 | 395 | 2009 A | Minimize! | [Question](https://codeforces.com/problemset/problem/2009/A) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/2009%20A%20-%20Minimize!)
 | 396 | 2009 B | osu!mania | [Question](https://codeforces.com/problemset/problem/2009/B) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/2009%20B%20-%20osu!mania)
 | 397 | 2009 C | The Legend of Freya the Frog | [Question](https://codeforces.com/problemset/problem/2009/C) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/2009%20C%20-%20The%20Legend%20of%20Freya%20the%20Frog)
+| 398 | 2009 D | Satyam and Counting | [Question](https://codeforces.com/problemset/problem/2009/D) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/2009%20D%20-%20Satyam%20and%20Counting)