atcoder/abc181B

Author: xirc

atcoder/abc181/B/main.cpp

@@ -0,0 +1,24 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+using ll = int64_t;
+using ff = long double;
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(0); cout.tie(0);
+
+    int N;
+
+    cin >> N;
+
+    ll sum = 0;
+    for (int i = 0; i < N; ++i) {
+        int A, B;
+        cin >> A >> B;
+        sum += ll(A + B) * (B - A + 1) / 2;
+    }
+    cout << sum << endl;
+
+    return 0;
+}