What is the correct way of implementing this custom priority_queue

» cpp » What is the correct way of implementing this custom priority_queue

By : user3100706

Date : January 12 2021, 09:11 PM

should help you out Comparison routines must return false if the two elements are equal, but your version returns true.
Try this instead

code :

bool compare(triplet x, triplet y) {

    if (x.data < y.data) {
        return true;
    }
    else {
        return false;
    }
}

bool compare(triplet x, triplet y) {    
    return x.data < y.data;
}

priority_queue<triplet, vector<triplet>, bool (*)(triplet, triplet)> pq1(compare);

Share :

iFrame Like Button on Facebook custom onClick, the correct way of implementing?

By : Mishka Beekeeper

Date : March 29 2020, 07:55 AM

help you fix your problem
then is there a way to remove the "share" box after clicking an XFBML button?

code :

.fb_edge_widget_with_comment span.fb_edge_comment_widget { display: none !important; }

c++ stl correct parameters to priority_queue

By : Weraphol Sukthai

Date : March 29 2020, 07:55 AM

it fixes the issue Below is the code snippet which is incorrect.

code :

#include <queue>
#include <iostream>

class edge{
public:
    int src;
    int dest;
    int wt;
};

struct less_weight {
    bool operator() (const edge& a, const edge& b) {
        return a.wt < b.wt;
    }
};

struct greater_weight {
    bool operator() (const edge& a, const edge& b) {
        return a.wt > b.wt;
    }
};

int main()
{
    std::priority_queue<int,std::vector<edge>,less_weight> prioritise_higher_weights;
    prioritise_higher_weights.push(edge{0, 1, 1 });
    prioritise_higher_weights.push(edge{1, 2, 2 });
    prioritise_higher_weights.push(edge{2, 3, 3 });

    std::priority_queue<int,std::vector<edge>,greater_weight> prioritise_lower_weights;
    prioritise_lower_weights.push(edge{0, 1, 1 });
    prioritise_lower_weights.push(edge{1, 2, 2 });
    prioritise_lower_weights.push(edge{2, 3, 3 });

    std::cout << prioritise_higher_weights.top().wt << std::endl;
    std::cout << prioritise_lower_weights.top().wt << std::endl;
}

3
1

How should I correct this priority_queue comparison function?

By : user3000833

Date : March 29 2020, 07:55 AM

I wish this help you Why you there is a priority_queue? Looks like we missing some information.
There are couple ways to fix issue with counts and lambda:

code :

vector<int> sortedByFreq(const vector<int>& nums)
{
    unordered_map<int, int> counts;
    for (auto i : nums)
        ++counts[i];

    vector<int> result = nums;
    std::sort(result.begin(), result.end(),
              [counts](auto a, auto b) {
                  return counts.at(a) > counts.at(b);
              });

    return result;
}

error: could not convert ‘minHeap’ from ‘std::priority_queue, std::greater >’ to ‘std::priority_queue

By : MGupta

Date : March 29 2020, 07:55 AM

wish helps you Your are trying to pass variable with priority_queue, greater > type, but your function expects priority_queue type.
Correct the prototype of function:

"error: no matching function for call to 'std::priority_queue<int>::priority_queue(int)' priority_queue<in

By : pg1024

Date : October 02 2020, 10:00 AM

hope this fix your issue related question
std::priority_queue doesn't have such constructor, but the below code implements what you want:

code :

std::vector<int> temporary_container(4);

std::priority_queue<int, std::vector<int>> pqueue (comparator, std::move(container));

std::vector<int> temporary_container;
temporary_container.reserve(4);

std::priority_queue<int, std::vector<int>> pqueue (comparator, std::move(container));