Added Numbers on whiteboard.cpp

Author: chhipanikhil9

Greedy/(CODEFORCES)C_Numbers_on_Whiteboard.cpp

@@ -0,0 +1,45 @@
+#include<bits/stdc++.h>
+#define fastio 	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
+#define int 	long long
+#define pb 		push_back		
+#define ff 		first
+#define ss 		second//typedef second ss;
+#define unmap  	unordered_map<int,int>
+#define	unset	unordered_set<int>
+#define maxpq  	priority_queue<int>
+#define minpq  	priority_queue<int, vector<int>, greater<int>>
+#define foton(i,n) for(int i=0;i<n;i++)
+#define	faton(i,a,n)	for(int i=a;i<=n;i++)
+#define mod 	1000000007
+const int inf = 10000007;
+#define endl "\n"
+using namespace std;
+
+int power(int b,int e,int m)
+{
+    if(e==0) return 1;
+    if(e&1) return b*power(b*b%m,e/2,m)%m;
+    return power(b*b%m,e/2,m);
+}
+int power(int b,int e)
+{
+    if(e==0) return 1;
+    if(e&1) return b*power(b*b,e/2);
+    return power(b*b,e/2);
+}
+
+int32_t main(){
+	fastio;
+	int t;cin>>t;
+	while(t--){
+		int n;cin>>n;
+    cout<<2<<endl;
+    int f = n;
+    for(int i=n-1;i>=1;i--){
+      cout<<f<<" "<<i<<endl;
+      f = (f+i+1)/2;
+    }
+	}
+	
+	return 0;
+}