Compare speeds of "uniq" operation to std::vector

uniq.cpp

#include <cstdlib>
#include <ctime>
#include <cassert>

#include <sys/time.h>
#include <unistd.h>

#include <set>
#include <vector>
#include <algorithm>
#include <iostream>
#include <iomanip>

using namespace std;

vector<int> uniq_set(const vector<int> &v) {
  set<int> s(begin(v), end(v));
  return vector<int>(begin(s), end(s));
}

vector<int> uniq_erase(const vector<int> &v) {
  vector<int> v2(v);

  v2.erase(unique(begin(v2), end(v2)), end(v2));
    
  return v2;
}

double wtime() {
  struct timeval t;
  gettimeofday(&t, NULL);
  return t.tv_sec + 1e-6*t.tv_usec;
}

#define measure(stmt, res) do {                 \
    double __t1 = wtime();                      \
    stmt;                                       \
    double __t2 = wtime();                      \
    res = __t2 - __t1;                          \
  } while(0)

int main(int argc, char**argv) {
  assert(argc == 2);
  srand(time(NULL));

  const auto N = atol(argv[1]);

  vector<int> v(N);
  for (int i = 0; i < N; i++) {
    v[i] = rand() % (N/10);
  }
  sort(begin(v), end(v));

  double t1, t2;
  measure(uniq_erase(v), t1);
  measure(uniq_set(v), t2);
  
  cout << "uniq_erase : " << scientific << t1 << " sec." << endl;
  cout << "uniq_set   : " << scientific << t2 << " sec." << endl;

  

  return 0;
}