From ac53767d8a224946f18329992ed50ac54db36d2b Mon Sep 17 00:00:00 2001
From: ShazidMahsrafi <shazid456@gmail.com>
Date: Sun, 2 Jun 2024 00:50:15 +0600
Subject: [PATCH] add 1981C

---
 .../1981C.cpp                                 | 79 +++++++++++++++++++
 Readme.md                                     |  1 +
 2 files changed, 80 insertions(+)
 create mode 100644 Codes/1981 C - Turtle and an Incomplete Sequence/1981C.cpp

diff --git a/Codes/1981 C - Turtle and an Incomplete Sequence/1981C.cpp b/Codes/1981 C - Turtle and an Incomplete Sequence/1981C.cpp
new file mode 100644
index 0000000..6b0e64b
--- /dev/null
+++ b/Codes/1981 C - Turtle and an Incomplete Sequence/1981C.cpp	
@@ -0,0 +1,79 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define endl '\n'
+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<int>v(n);
+    for(auto &i:v)  cin>>i;
+    int prev=-1;
+    for(int i=0; i<n; ++i)
+    {
+        if(v[i]==-1)    continue;
+        if(prev==-1)
+        {
+            for(int j=i-1; j>=0; --j)
+            {
+                if(v[j+1]>1)    v[j]=v[j+1]/2;
+                else v[j]=v[j+1]*2;
+            }
+            prev=i;
+            continue;
+        }
+        int l=prev, r=i;
+        while(r-l>1)
+        {
+            if(v[r]>v[l])
+            {
+                v[r-1]=v[r]/2;
+                r--;
+            }
+            else
+            {
+                if(v[l]>1)  v[l+1]=v[l]/2;
+                else    v[l+1]=v[l]*2;
+                l++;
+            }
+        }
+        prev=i;
+    }
+    if(prev<n-1)
+    {
+        if(prev==-1)
+        {
+            v[0]=1;
+            prev=0;
+        }
+        for(int i=prev+1; i<n; ++i)
+        {
+            if(v[i-1]>1) v[i]=v[i-1]/2;
+            else    v[i]=v[i-1]*2;
+        }
+    }
+    for(int i=0; i<n-1; ++i)
+    {
+        if(v[i]!=v[i+1]/2 && v[i+1]!=v[i]/2)
+        {
+            cout<<-1<<endl;
+            return;
+        }
+    }
+    for(auto i:v)   cout<<i<<" ";
+    cout<<endl;
+}
+
+signed main()
+{
+    ios_base::sync_with_stdio(false), cin.tie(nullptr);
+    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 c9c0312..188f548 100644
--- a/Readme.md
+++ b/Readme.md
@@ -330,6 +330,7 @@ This repository contains my solutions of Codeforces problems. They are in C++ la
 | 318 | 1976 B | Increase Decrease Copy | [Question](https://codeforces.com/problemset/problem/1976/B) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1976%20B%20-%20Increase%20Decrease%20Copy)
 | 319 | 1981 A | Turtle and Piggy Are Playing a Game | [Question](https://codeforces.com/problemset/problem/1981/A) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1981%20A%20-%20Turtle%20and%20Piggy%20Are%20Playing%20a%20Game)
 | 320 | 1981 B | Turtle and an Infinite Sequence | [Question](https://codeforces.com/problemset/problem/1981/B) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1981%20B%20-%20Turtle%20and%20an%20Infinite%20Sequence)
+| 321 | 1981 C | Turtle and an Incomplete Sequence | [Question](https://codeforces.com/problemset/problem/1981/C) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1981%20C%20-%20Turtle%20and%20an%20Incomplete%20Sequence)