day1_2

// In this challenge, we practice calculating the interquartile range. //

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <iomanip>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int input, size;
    cin >> size;
    vector<int> elements, frequencies;
    for(int i = 0; i < size; i++){
        cin >> input;
        elements.push_back(input);
    } 
    for(int i = 0; i < size; i++){
        cin >> input; 
        frequencies.push_back(input);
    }
    vector<int> finalVector;
    int curr = 0;
    for(int i = 0; i < size; i++){
        curr = frequencies[i];
        for(int j = 0; j < curr; j++){
            finalVector.push_back(elements[i]);
        }
    }
    std::sort(finalVector.begin(), finalVector.end());
    vector<int> lowerHalf, upperHalf;
    if(finalVector.size() % 2 != 0){
        for(long unsigned i = 0; i < finalVector.size() / 2; i++){
            lowerHalf.push_back(finalVector[i]);
        }
        for(long unsigned i = finalVector.size(); i > finalVector.size() / 2; i--){
            upperHalf.push_back(finalVector[i]);
        }
    } else {
        for(long unsigned i = 0; i < finalVector.size() / 2; i++){
            lowerHalf.push_back(finalVector[i]);
        }
        for(long unsigned i = finalVector.size(); i > finalVector.size() / 2; i--){
            upperHalf.push_back(finalVector[i]);
        }
    }
    float interquartile = 0;
    if(lowerHalf.size() % 2 != 0) {
        interquartile = upperHalf[upperHalf.size()/2] - lowerHalf[lowerHalf.size()/2];
    } else {
        float upper = (upperHalf[upperHalf.size()/2] + upperHalf[(upperHalf.size()/2)-1])/2;
        float lower = (lowerHalf[lowerHalf.size()/2] + lowerHalf[(lowerHalf.size()/2)-1])/2;
        interquartile = upper - lower;
    }
    cout << fixed << setprecision(1) << interquartile;
    return 0;
}