find minimum element in a sorted and rotated array

Need to handle duplicates also

#include <stdio.h>
 
int min(int x, int y) { return (x < y)? x :y; }
 
int findMin(int arr[], int low, int high)
{
    // incase when array is not rotated 
    if (high < low)  return arr[0];
 
    // If there is only one element left
    if (high == low) return arr[low];
 
    // Find mid
    int mid = (low + high)/2;
 
    // Check if element (mid+1) is minimum element. Consider the cases like {1, 1, 0, 1}
    if (mid < high && arr[mid+1] < arr[mid])
       return arr[mid+1];
 
    // This case causes O(n) time
    if (arr[low] == arr[mid] && arr[high] == arr[mid])
        return min(findMin(arr, low, mid-1), findMin(arr, mid+1, high));
 
    // Check if mid itself is minimum element
    if (mid > low && arr[mid] < arr[mid - 1])
       return arr[mid];
 
    // Decide whether we need to go to left half or right half
    if (arr[high] > arr[mid])
       return findMin(arr, low, mid-1);
    return findMin(arr, mid+1, high);
}

Atoi function in c

ATOI FUNCTION

#include<stdio.h>
#include<stdlib.h>

int main ()
{
    int i;
    char buffer [256];

     printf ("Enter a number: ");
     fgets (buffer, 256, stdin);

     i = atoi (buffer);
     printf ("The value entered is %d.",i);
     return 0;
}

OWN ATOI FUNCTION

#include <stdio.h>
 
// A utility function to check whether x is numeric
bool isNumericChar(char x)
{
    return (x >= '0' && x <= '9')? true: false;
}
 
int myAtoi(char *str)
{
    if (*str == NULL)
       return 0;
    int res = 0;  // Initialize result
    int sign = 1;  // Initialize sign as positive
    int i = 0;  // Initialize index of first digit
 
    if (str[0] == '-')
    {
        sign = -1;
        i++;  // Also update index of first digit
    }
 
    // Iterate through all digits of input string and update result
    for (; str[i] != ''; ++i)
    {
        if (isNumericChar(str[i]) == false)
            return 0;
        res = res*10 + str[i] - '0';
    }

    return sign*res;
}
 
// Driver program to test above function
int main()
{
    char str[] = "-134";
    int val = myAtoi(str);
    printf("%d ", val);
    return 0;
}

Parsing / Reading XML file in Java

Sample XML file

<?xml version="1.0"?>
<students>
    <student>
        <name>John</name>
        <grade>B</grade>
        <age>12</age>
    </student>
    <student>
        <name>Mary</name>
        <grade>A</grade>
        <age>11</age>
    </student>
    <student>
        <name>Simon</name>
        <grade>A</grade>
        <age>18</age>
    </student>
</students>

Java code to parse above XML

import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
 
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
 
public class XMLParser {
 
    public void getAllUserNames(String fileName) {
        try {
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();
            File file = new File(fileName);
            if (file.exists()) {
                Document doc = db.parse(file);
                Element docEle = doc.getDocumentElement();
 
                // Print root element of the document
                System.out.println("Root element of the document: "
                        + docEle.getNodeName());
 
                NodeList studentList = docEle.getElementsByTagName("student");
 
                // Print total student elements in document
                System.out
                        .println("Total students: " + studentList.getLength());
 
                if (studentList != null && studentList.getLength() > 0) {
                    for (int i = 0; i < studentList.getLength(); i++) {
 
                        Node node = studentList.item(i);
 
                        if (node.getNodeType() == Node.ELEMENT_NODE) {
 
                            System.out
                                    .println("=====================");
 
                            Element e = (Element) node;
                            NodeList nodeList = e.getElementsByTagName("name");
                            System.out.println("Name: "
                                    + nodeList.item(0).getChildNodes().item(0)
                                            .getNodeValue());
 
                            nodeList = e.getElementsByTagName("grade");
                            System.out.println("Grade: "
                                    + nodeList.item(0).getChildNodes().item(0)
                                            .getNodeValue());
 
                            nodeList = e.getElementsByTagName("age");
                            System.out.println("Age: "
                                    + nodeList.item(0).getChildNodes().item(0)
                                            .getNodeValue());
                        }
                    }
                } else {
                    System.exit(1);
                }
            }
        } catch (Exception e) {
            System.out.println(e);
        }
    }
    public static void main(String[] args) {
 
        XMLParser parser = new XMLParser();
        parser.getAllUserNames("c:\\test.xml");
    }
}

Few Java snippets

String a = String.valueOf(2);   //integer to numeric string
int i = Integer.parseInt(a); //numeric string to an int

String to Date

SimpleDateFormat format = new SimpleDateFormat( "dd.MM.yyyy" );
Date date = format.parse( myString );

Creating JSON data in Java

import org.json.JSONObject;
...
...
JSONObject json = new JSONObject();
json.put("city", "Mumbai");
json.put("country", "India");
...
String output = json.toString();
...

Java Singleton example

public class SimpleSingleton {
    private static SimpleSingleton singleInstance =  new SimpleSingleton();
 
    //Marking default constructor private
    //to avoid direct instantiation.
    private SimpleSingleton() {
    }
 
    //Get instance for class SimpleSingleton
    public static SimpleSingleton getInstance() {
 
        return singleInstance;
    }
}

Send HTTP request & fetching data using Java

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
 
public class Main {
    public static void main(String[] args)  {
        try {
            URL my_url = new URL("http://www.xyz.com/");
            BufferedReader br = new BufferedReader(new InputStreamReader(my_url.openStream()));
            String strTemp = "";
            while(null != (strTemp = br.readLine())){
            System.out.println(strTemp);
        }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

Convert Array to Map in Java

import java.util.Map;
import org.apache.commons.lang.ArrayUtils;
 
public class Main {
 
  public static void main(String[] args) {
    String[][] countries = { { "United States", "New York" }, { "United Kingdom", "London" },
        { "Netherland", "Amsterdam" }, { "Japan", "Tokyo" }, { "France", "Paris" } };
 
    Map countryCapitals = ArrayUtils.toMap(countries);
 
    System.out.println("Capital of Japan is " + countryCapitals.get("Japan"));
    System.out.println("Capital of France is " + countryCapitals.get("France"));
  }
}

HTTP Proxy setting in Java

System.getProperties().put("http.proxyHost", "someProxyURL");
System.getProperties().put("http.proxyPort", "someProxyPort");
System.getProperties().put("http.proxyUser", "someUserName");
System.getProperties().put("http.proxyPassword", "somePassword");