initial commit

1818B Indivisible/1818B.cpp

@@ -0,0 +1,30 @@
+#include<bits/stdc++.h>
+using namespace std;
+using ll = long long;
+
+void solve()
+{
+    int n;
+    cin>>n;
+    if(n==1) cout<<"1"<<endl;
+    else if(n%2!=0) cout<<"-1"<<endl;
+    else
+    {
+        for(int i=1; i<=n; i+=2)
+        {
+            cout<<i+1<<" "<<i<<" ";
+        }
+        cout<<endl;
+    }
+}
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int TC = 1;
+    cin >> TC;
+    cin.ignore();
+    while (TC--) solve();
+}