Breaking News: Grepper is joining You.com. Read the official announcement!

c++ sorting and keeping track of indexes

Powerful Penguin answered on August 28, 2020 Popularity 6/10 Helpfulness 2/10

answer c++ sorting and keeping track of indexes

c++ sorting and keeping track of indexes

Comment

#include <iostream>
#include <vector>
#include <numeric>      // std::iota
#include <algorithm>    // std::sort, std::stable_sort

using namespace std;

template <typename T>
vector<size_t> sort_indexes(const vector<T> &v) {

  // initialize original index locations
  vector<size_t> idx(v.size());
  iota(idx.begin(), idx.end(), 0);

  // sort indexes based on comparing values in v
  // using std::stable_sort instead of std::sort
  // to avoid unnecessary index re-orderings
  // when v contains elements of equal values 
  stable_sort(idx.begin(), idx.end(),
       [&v](size_t i1, size_t i2) {return v[i1] < v[i2];});

  return idx;
}

Popularity 6/10 Helpfulness 2/10 Language cpp

Source: stackoverflow.com

Tags: c++ sorting

Link to this answer
Share Copy Link