C++ Efficiently Calculating a Running Median [duplicate]

Answer 1

#include
#include
#include
#include          
#include 

typedef priority_queue type_H_low;
typedef priority_queue, std::greater > type_H_high;

size_t signum(int left, int right) {
    if (left == right){
        return 0;
    }
    return (left < right)?-1:1;
}

void get_median( unsigned int x_i, unsigned int &m, type_H_low *l, type_H_high *r) {

    switch (signum( l->size(), r->size() )) {
    case 1: // There are more elements in left (max) heap
        if (x_i < m) {
            r->push(l->top());
            l->pop();
            l->push(x_i);
        } else {
            r->push(x_i);
        }
        break;

    case 0: // The left and right heaps contain same number of elements
        if (x_i < m){
            l->push(x_i);
        } else {
            r->push(x_i);
        }
        break;

    case -1: // There are more elements in right (min) heap
        if (x_i < m){
            l->push(x_i);
        } else {
            l->push(r->top());
            r->pop();
            r->push(x_i);
        }
        break;
    }

    if (l->size() == r->size()){
        m = l->top();
    } else if (l->size() > r->size()){
        m = l->top();
    } else {
        m = r->top();
    }

    return;
}

void print_median(vector v) {
    unsigned int median = 0;
    long int sum = 0;
    type_H_low  H_low;
    type_H_high H_high;

    for (vector::iterator x_i = v.begin(); x_i != v.end(); x_i++) {
        get_median(*x_i, median, &H_low, &H_high);
        std::cout << median << std::endl;
    }
}