11136 solved

11136.cpp

@@ -0,0 +1,41 @@
+#include <iostream>
+#include <set>
+using namespace std;
+
+int main(void) {
+  int n, k, bill;
+  unsigned long long result;
+  multiset<int> bills;
+  multiset<int>::iterator it1;
+  multiset<int>::reverse_iterator it2;
+
+  while (cin >> n) {
+    if (n == 0)
+      break;
+
+    bills.clear();
+    result = 0;
+
+    for (int i = 0; i < n; i++) {
+      cin >> k;
+      while (k--) {
+        cin >> bill;
+        bills.insert(bill);
+      }
+
+      it1 = bills.begin();
+      it2 = bills.rbegin();
+      bill = *it2;
+
+      result += *it2 - *it1;
+
+      bills.erase(it1);
+      it1 = bills.find(bill);
+      bills.erase(it1);
+    }
+
+    cout << result << endl;
+  }
+
+  return 0;
+}