【leetcode】217. Contains Duplicate

#include 

#include 
#include 
#include 
#include 

using namespace std;

bool containsDuplicate(vector<int>& nums) {
  unordered_set<int> us;
  for( auto i : nums) {
    auto it = us.find(i);
    if( it == us.end() ) {
      us.insert(i);

    } else {
      return true;
    }

  }
  return false;

}

int main(int argc,char *argv[]) {

  struct  timeval    tv1,tv2;
  struct  timezone   tz;
  int time1 = gettimeofday(&tv1,&tz);

  vector<int> v = {1,2,3,4,5,6,7,8,9};
  cout<< containsDuplicate(v) << endl;
  v.push_back(3);
  cout<int time2 = gettimeofday(&tv2,&tz);
  cout << "time consuming(local machine/leetcode server):"<"leetcode server time consuming should be less than 500ms"<"us/"<<0.11*( tv2.tv_usec - tv1.tv_usec )<<"ms"<< endl;

  return 0;
}

总结

1. 采用unorderede_set来简化算法设计，利用其自身可以快速实现元素插入和查找的性质来实现。
2. 采用C++11编写的第一道LeetCode代码，按照Google C++ style 的要求进行代码格式化。