Riddles

From OriWiki

The biggest difference

Suppose you are given a vector of values of a stock. Your mission is is to find the best time to buy and the best time to sell it. The algorithm should be efficient.

void biggest_difference(const vector<int>& v) {
  int min=0,max=0,candidate_min=0;
  for(unsigned int i=1; i<v.size(); ++i) {
    if(v[i] - v[candidate_min] > v[max] - v[min]) {
      min = candidate_min;
      max = i;
    } 
    else if(v[i] < v[candidate_min]) 
      candidate_min = i; 
  }
  cout << min << ',' << max << '\n'; 
}