Margarite and the best present

Author: seikhchilli

1080B.cpp

@@ -0,0 +1,42 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+#define ll long long
+#define '\n' endl
+#define debug(n) cout<<(n)<<endl;
+const ll INF = 2e18 + 99
+
+int main(){
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
+
+  int t;
+  cin>>t;
+  long long l, r;
+  while(t--){
+
+    cin>>l>>r;
+    long long odd_l, odd_r;
+    l--;
+    if(l % 2 == 0){
+      odd_l = l/2 * l/2;
+    }
+    else{
+      odd_l = (l/2 + 1) * (l/2 + 1);
+    }
+    long long even_l = l/2 * (l/2 + 1);
+    if(r % 2 == 0){
+      odd_r = r/2 * r/2;
+    }
+    else{
+      odd_r = (r/2 + 1) * (r/2 + 1);
+    }
+    long long even_r = r/2 * (r/2 + 1);
+
+    long long even_s = even_r - even_l;
+    long long odd_s = odd_r - odd_l;
+
+    cout<<(even_s - odd_s)<<"\n";
+  }
+  return 0;
+}