uva 11136 Hoax or what

题目：Hoax or what

思路：STL中的multiset。

代码：

#include <cstdio>#include <iostream>#include <algorithm>#include <stack>#include <queue>#include <deque>#include <set>#include <cstring>#include <map>using namespace std;multiset<int> s;int main() {int n;while(~scanf("%d",&n)&&n!=0) {long long ans=0;s.clear();for(int i=0; i<n; i++) {int k;scanf("%d",&k);for(int j=0; j<k; j++) {int x;scanf("%d",&x);s.insert(x);}int a=*(s.begin()),b=*(--s.end());ans=ans+b-a;s.erase(s.begin()),s.erase(--s.end());}printf("%lld\n",ans);}return 0;}