initial commit

1367B Even Array/1367B.cpp

@@ -0,0 +1,35 @@
+#include<bits/stdc++.h>
+using namespace std;
+using ll = long long;
+
+
+void solve()
+{
+    int n;
+    cin>>n;
+    int odd_ct=0, even_ct=0;
+    for(int i=0; i < n; ++i)
+    {
+        int x;
+        cin>>x;
+        if(i%2==0 && x%2!=0)
+            even_ct++;
+        else if(i%2!=0 && x%2==0)
+            odd_ct++;
+    }
+    if(odd_ct!=even_ct)
+        cout<<-1<<endl;
+    else
+        cout<<odd_ct<<endl;
+}
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int TC = 1;
+    cin >> TC;
+    cin.ignore();
+    while (TC--) solve();
+}