Untitled Page

1. Meandering Array
public static List<Integer> meanderingArray(List<Integer> list) {
    Collections.sort(list);
    List<Integer> res = new ArrayList<>();
    int i = list.size() - 1, j = 0;

    while (j <= i) {
        res.add(list.get(i--));
        if (j <= i) res.add(list.get(j++));
    }
    return res;
}

2. Project Estimates
public static int countPairs(List<Integer> costs, int target) {
    Set<Integer> set = new HashSet<>(costs);
    int count = 0;

    for (int x : costs)
        if (set.contains(x + target)) count++;

    return count;
}
3. Ensemble Model Selection
public static int countValidEnsembles(
        List<Integer> a, int minModels, int minAccuracy, int maxAccuracy) {

    int n = 0;
    for (int x : a)
        if (x >= minAccuracy && x <= maxAccuracy) n++;

    int count = 0;
    for (int mask = 1; mask < (1 << n); mask++)
        if (Integer.bitCount(mask) >= minModels) count++;

    return count;
}
4. Rover Control
public static int roverControl(int n, List<String> commands) {
    int r = 0, c = 0;

    for (String s : commands) {
        switch (s) {
            case "UP":    if (r > 0) r--; break;
            case "DOWN":  if (r < n - 1) r++; break;
            case "LEFT":  if (c > 0) c--; break;
            case "RIGHT": if (c < n - 1) c++; break;
        }
    }
    return r * n + c;
}
5. Transaction Sequence Optimization
public static int maxTransactions(List<Integer> transactions) {
    transactions.sort(Collections.reverseOrder());

    long sum = 0;
    int count = 0;

    for (int x : transactions) {
        if (sum + x <= 0) break;
        sum += x;
        count++;
    }
    return count;}
1. Election Exit Poll Distribution Report
SELECT state,GROUP_CONCAT(CONCAT(name,' x ',c) ORDER BY c DESC,name) votes
FROM (SELECT state,CONCAT(first_name,' ',last_name) name,COUNT(*) c
FROM results JOIN candidates ON candidate_id=id
GROUP BY state,id,name) t
GROUP BY state ORDER BY state;
2. Long-term vs Short-term Investment Analysis
SELECT name client_name,
(SELECT FORMAT(SUM(invested_amount),2) FROM bonds_investments WHERE client_id=clients.id) total_invested_in_bonds,
(SELECT FORMAT(SUM(invested_amount),2) FROM stocks_investments WHERE client_id=clients.id) total_invested_in_stocks
FROM clients
HAVING total_invested_in_bonds>5000
ORDER BY total_invested_in_bonds DESC;
3. Advertising Product Engagement Metrics Report
WITH s AS (
 SELECT SUM(is_confirmed=1) v FROM views
), c AS (
 SELECT SUM(is_confirmed=1) c FROM clicks
)
SELECT 'Total Views' metric_name,CAST(v AS CHAR) metric_value FROM s
UNION ALL
SELECT 'Total Clicks',CAST(c AS CHAR) FROM c
UNION ALL
SELECT 'Click Through Rate',CAST(ROUND(c*100/v,2) AS DECIMAL(10,2))
FROM s CROSS JOIN c;
4. Cryptocurrency Portfolio Analysis
SELECT crypto_type,crypto_name,
CONCAT('$',CAST(ROUND(total_value,2) AS DECIMAL(15,2))) total_value
FROM (
 (SELECT 'Coin' crypto_type,name crypto_name,
 quantity*REPLACE(unit_value,'$','') total_value
 FROM coins ORDER BY total_value DESC LIMIT 5)
 UNION ALL
 (SELECT 'Token',name,quantity*REPLACE(unit_value,'$','')
 FROM tokens ORDER BY total_value DESC LIMIT 5)
) t
ORDER BY crypto_type,total_value DESC;


1.Maximum Transfer

import java.net.URI;
import java.net.http.*;
import java.io.IOException;
import java.util.*;
import com.google.gson.*;

class Solution {
    public static String[] transferAmount(String name, String city) {
        double credit = 0, debit = 0;
        long page = 1, totalPages = 1;
        HttpClient client = HttpClient.newHttpClient();

        while (page <= totalPages) {
            String url = "https://jsonmock.hackerrank.com/api/transactions?page=" + page;
            HttpRequest req = HttpRequest.newBuilder()
                .uri(URI.create(url))
                .header("Accept", "application/json")
                .GET().build();

            try {
                HttpResponse<String> res = client.send(
                    req, HttpResponse.BodyHandlers.ofString());

                JsonObject json = JsonParser.parseString(res.body()).getAsJsonObject();
                totalPages = json.get("total_pages").getAsLong();

                for (JsonElement e : json.getAsJsonArray("data")) {
                    JsonObject t = e.getAsJsonObject();

                    if (t.get("userName").getAsString().equals(name)
                        && t.getAsJsonObject("location").get("city")
                            .getAsString().equals(city)) {

                        double amount = Double.parseDouble(
                            t.get("amount").getAsString()
                                .replace("$", "").replace(",", ""));

                        String type = t.get("txnType").getAsString();

                        if (type.equals("credit"))
                            credit = Math.max(credit, amount);
                        else if (type.equals("debit"))
                            debit = Math.max(debit, amount);
                    }
                }
            } catch (IOException | InterruptedException e) {
                Thread.currentThread().interrupt();
                return new String[]{"0.00","0.00"};
            }
            page++;
        }

        return new String[]{
            String.format("$%,.2f", credit),
            String.format("$%,.2f", debit)
        };
    }
}

2.Future Events


import java.net.URI;
import java.net.http.*;
import java.time.Instant;
import java.io.IOException;
import java.util.*;
import com.google.gson.*;

class Solution {
    public static List<String> futureEvents(String country, long plannedDate) {
        List<String> result = new ArrayList<>();
        HttpClient client = HttpClient.newHttpClient();
        long page = 1, totalPages = 1, firstDate = Long.MAX_VALUE, lastDate = Long.MIN_VALUE;
        String first = "", last = "";

        while (page <= totalPages) {
            String url = "https://jsonmock.hackerrank.com/api/events?country="
                    + country + "&page=" + page;
            HttpRequest req = HttpRequest.newBuilder()
                    .uri(URI.create(url)).GET().build();

            try {
                HttpResponse<String> res = client.send(
                        req, HttpResponse.BodyHandlers.ofString());
                JsonObject json = JsonParser.parseString(res.body()).getAsJsonObject();
                totalPages = json.get("total_pages").getAsLong();

                for (JsonElement e : json.getAsJsonArray("data")) {
                    JsonObject event = e.getAsJsonObject();
                    long date = Instant.parse(
                            event.get("date").getAsString()).toEpochMilli();

                    if (date > plannedDate) {
                        String name = event.get("name").getAsString();

                        if (date < firstDate) {
                            firstDate = date;
                            first = name;
                        }
                        if (date > lastDate) {
                            lastDate = date;
                            last = name;
                        }
                    }
                }
            } catch (IOException | InterruptedException e) {
                Thread.currentThread().interrupt();
                return Arrays.asList("", "");
            }
            page++;
        }

        result.add(first);
        result.add(last);
        return result;
    }
}

3.City Weather


import java.net.URI;
import java.net.http.*;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.io.IOException;
import java.util.*;
import com.google.gson.*;

class Solution {
    public static String[] weatherStation(String keyword) {
        List<String> result = new ArrayList<>();
        HttpClient client = HttpClient.newHttpClient();
        long page = 1, totalPages = 1;

        while (page <= totalPages) {
            String url = "https://jsonmock.hackerrank.com/api/weather/search?name="
                    + URLEncoder.encode(keyword, StandardCharsets.UTF_8)
                    + "&page=" + page;

            HttpRequest req = HttpRequest.newBuilder()
                    .uri(URI.create(url)).GET().build();

            try {
                HttpResponse<String> res = client.send(
                        req, HttpResponse.BodyHandlers.ofString());
                JsonObject json = JsonParser.parseString(res.body()).getAsJsonObject();
                totalPages = json.get("total_pages").getAsLong();

                for (JsonElement e : json.getAsJsonArray("data")) {
                    JsonObject city = e.getAsJsonObject();
                    String name = city.get("name").getAsString();
                    String temp = city.get("weather").getAsString()
                            .replaceAll("[^0-9.-]", "");

                    JsonArray status = city.getAsJsonArray("status");
                    String wind = status.get(0).getAsString()
                            .replaceAll("[^0-9.-]", "");
                    String humidity = status.get(1).getAsString()
                            .replaceAll("[^0-9.-]", "");

                    result.add(name + "," + temp + "," + wind + "," + humidity);
                }
            } catch (IOException e) {
                return new String[0];
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                return new String[0];
            }
            page++;
        }

        Collections.sort(result);
        return result.toArray(new String[0]);
    }
}


4.Pulse Rate

import java.net.URI;
import java.net.http.*;
import java.io.IOException;
import com.google.gson.*;

class Solution {
    public static int pulseRate(String diagnosisName, int doctorId) {
        HttpClient client = HttpClient.newHttpClient();
        long page = 1, totalPages = 1, sum = 0, count = 0;

        while (page <= totalPages) {
            String url = "https://jsonmock.hackerrank.com/api/medical_records?page=" + page;
            HttpRequest req = HttpRequest.newBuilder()
                    .uri(URI.create(url)).GET().build();

            try {
                HttpResponse<String> res = client.send(
                        req, HttpResponse.BodyHandlers.ofString());
                JsonObject json = JsonParser.parseString(res.body()).getAsJsonObject();
                totalPages = json.get("total_pages").getAsLong();

                for (JsonElement e : json.getAsJsonArray("data")) {
                    JsonObject record = e.getAsJsonObject();
                    JsonObject diagnosis = record.getAsJsonObject("diagnosis");
                    JsonObject doctor = record.getAsJsonObject("doctor");

                    if (diagnosis.get("name").getAsString().equals(diagnosisName)
                            && doctor.get("id").getAsInt() == doctorId) {
                        sum += record.getAsJsonObject("vitals").get("pulse").getAsInt();
                        count++;
                    }
                }
            } catch (IOException e) {
                return 0;
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                return 0;
            }
            page++;
        }

        return count == 0 ? 0 : (int) (sum / count);
    }
}

5. TV Show

import java.net.URI;
import java.net.http.*;
import java.util.*;
import com.google.gson.*;

class Result {

    public static List<String> showsInProduction(int startYear, int endYear)
            throws Exception {

        List<String> result = new ArrayList<>();
        HttpClient client = HttpClient.newHttpClient();
        int page = 1, totalPages = 1;

        while (page <= totalPages) {
            String url = "https://jsonmock.hackerrank.com/api/tvseries?page=" + page;

            HttpRequest request = HttpRequest.newBuilder()
                    .uri(URI.create(url))
                    .GET()
                    .build();

            HttpResponse<String> response = client.send(
                    request, HttpResponse.BodyHandlers.ofString());

            JsonObject json = JsonParser.parseString(response.body()).getAsJsonObject();
            totalPages = json.get("total_pages").getAsInt();
            JsonArray data = json.getAsJsonArray("data");

            for (JsonElement item : data) {
                JsonObject show = item.getAsJsonObject();
                String name = show.get("name").getAsString();
                String runtime = show.get("runtime_of_series").getAsString();

                if (runtime.matches("^\\([IVXLCDM]+\\) .*")) {
                    runtime = runtime.substring(runtime.indexOf(") ") + 2);
                }

                String years = runtime.replaceAll(
                        ".*\\((\\d{4})(?:-(\\d{4}))?\\).*", "$1 $2");

                String[] y = years.trim().split("\\s+");

                int start = Integer.parseInt(y[0]);
                int end = y.length > 1 ? Integer.parseInt(y[1]) : start;

                if (start >= startYear &&
                    (endYear == -1 ? end == -1 : end != -1 && end <= endYear)) {
                    result.add(name);
                }
            }

            page++;
        }

        Collections.sort(result);
        return result;
    }
}