std::min_elementで0でない最小値を探すための比較関数 ref: http://qiita.com/items/e7918d3416c5ae6a1102

min.cpp

#include <iostream>
#include <vector>
#include <algorithm>
using std::vector;
using std::cout;
using std::endl;
int main() {
  vector<int> a = {5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5};
  auto min = min_element(a.begin(), a.end(), [](int a, int b) {
    return ((a != 0) && (b == 0)) || a < b;
  });
  cout << distance(a.begin(), min) << endl;
  return 0;
}

min_emelent.hpp

if (comp(*first, *smallest)) {
  smallest = first;
}