10亿个浮点数,求出其中最大的10000个. .

http://blog.csdn.net/cnki_ok/article/details/7863810

 

#include "stdafx.h"#include <vector>#include <iostream>#include <algorithm>#include <functional> // for greater<>using namespace std;int _tmain(int argc, _TCHAR* argv[]){  vector<float> bigs(10000,0);  vector<float>::iterator it;  // Init vector data  for (it = bigs.begin(); it != bigs.end(); it++)  {    *it = (float)rand()/7; // random values;  }  cout << bigs.size() << endl;  make_heap(bigs.begin(),bigs.end(), greater<float>()); // The first one is the smallest one!  float ff;  for (int i = 0; i < 1000000000; i++)  {    ff = (float) rand() / 7;    if (ff > bigs.front()) // replace the first one ?    {      // set the smallest one to the end!      pop_heap(bigs.begin(), bigs.end(), greater<float>());       // remove the last/smallest one      bigs.pop_back();       // add to the last one      bigs.push_back(ff);       // mask heap again, the first one is still the smallest one      push_heap(bigs.begin(),bigs.end(),greater<float>());    }  }  // sort by ascent  sort_heap(bigs.begin(), bigs.end(), greater<float>());   // sort by descent  //sort_heap(bigs.begin(), bigs.end());   //sort_heap(bigs.begin(), bigs.end(), less<float>());   return 0;}