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Articles on Trending Technologies
Technical articles with clear explanations and examples
Character class: intersection - Java regular expressions
The character classes in Java regular expression is defined using the square brackets "[ ]", this subexpression matches a single character from the specified or, set of possible characters. For example the regular expression [abc] matches a single character a or, b or, c.The intersection variant of the character class allows you to match a character which is common in the ranges that have intersection relation between them.An intersection relation between ranges is defined using && i.e. the expression [a-z&&[r-u]] matches a single character from r to u.Exampleimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample1 { public static ...
Read MoreClimbing Stairs in C++
There are n stairs. One person will go to 1st to nth stairs. Maximum how many stairs he/she can cross in one step is also given. With this information, we have to find possible ways to go to the nth stairs. Let us consider one can cross a maximum two stairs in each step. So we can find recursive relations to solve this problem. One can move to nth stair, either from (n-1)th stair or from (n-2)th stair. So ways(n) = ways(n-1) + ways(n-2).Suppose the number of stairs, say 10, the maximum number of stairs that can be jumped in ...
Read MoreCharacter class: subtraction - Java regular expressions
You can subtract one range from other and use it as new range. You can achieve this by using two variants of character classes i.e. negation and intersection.For example the intersection of ranges [a-l] and [^e-h] gives you the characters a to l as rage subtracting the characters [e-h]Exampleimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample1 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter input text: "); String input = sc.nextLine(); String regex = "[a-l&&[^e-h]]"; //Creating a pattern ...
Read MoreRegular Expression Q Metacharacter in Java
The subexpression/metacharacter "\Q" escapes all characters up to "\E" i.e. you can escape metacharacters in the regular expressions by placing them in between \Q and \E. For example, the expression [aeiou] matches the strings with vowel letters in it.Example import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class SampleProgram { public static void main( String args[] ) { String regex = "[aeiou]"; Scanner sc = new Scanner(System.in); System.out.println("Enter input string: "); String input = sc.nextLine(); //Creating a Pattern object Pattern pattern = Pattern.compile(regex); ...
Read MoreJava program to remove all numbers in a string except "1" and "2"?
The regular expression "(?digit(?!\d)" matches the digit specified.The replaceAll() method accepts two strings: a regular expression pattern and, the replacement string and replaces the pattern with the specified string.Therefore, to remove all numbers in a string except 1 and 2, replace the regular expressions 1 and 2 with one and two respectively and replace all the other digits with an empty string.Exampleimport java.util.Scanner; public class RegexExample { public static void main(String args[]) { //Reading String from user System.out.println("Enter a String"); Scanner sc = new Scanner(System.in); String input ...
Read MorePascal's Triangle in C++
Pascal’s triangle is an array of binomial coefficients. The top row is numbered as n=0, and in each row are numbered from the left beginning with k = 0. Each number is found by adding two numbers which are residing in the previous row and exactly top of the current cell. It is also being formed by finding (𝑛𝑘) for row number n and column number k.Suppose the input is 10, then the output will be like − 1 1 1 ...
Read MoreMinimum sum of two numbers formed from digits of an array in C++
DescriptionGiven an array of digits which contains values from 0 to 9. The task is to find the minimum possible sum of two numbers formed from digits of the array. Please note that we have to use all digits of given arrayExampleIf input array is {7, 5, 1, 3, 2, 4} then minimum sum is 382 as, we can create two number 135 and 247.AlgorithmSort the array in ascending orderCreate two number by picking a digit from sorted array alternatively i.e. from even and odd indexExample#include using namespace std; int getMinSum(int *arr, int n) { sort(arr, arr + ...
Read MorePrint all subsequences of a string using Iterative Method in C++
In this problem, we are given a string and we have to find the substring from the given string. The substring to be found should start with a vowel and end with constant character.A string is an array of characters.The substring that is to be generated in this problem can be generated by deleting some characters of the string. And without changing the order of the string.Input: ‘abc’ Output: ab, ac, abcTo solve this problem, we will iterate the string and fix vowels and check for the next sequence. Let’s see an algorithm to find a solution −AlgorithmStep 1: Iterate ...
Read MoreMinimum sum path between two leaves of a binary trees in C++
Problem statementGiven a binary tree in which each node element contains a number. The task is to find the minimum possible sum from one leaf node to another.ExampleIn above tree minimum sub path is -6 as follows: (-4) + 3 + 2 + (-8) + 1AlgorithmThe idea is to maintain two values in recursive calls −Minimum root to leaf path sum for the subtree rooted under current nodeThe minimum path sum between leavesFor every visited node X, we have to find the minimum root to leaf sum in left and right sub trees of X. Then add the two values ...
Read MorePrint all subarrays with 0 sum in C++
In this problem, we are given an array of integer values and we have to print all those subarrays from this array that have the sum equal to 0.Let’s take an example to understand the topic better, Input: array = [-5, 0, 2, 3, -3, 4, -1] Output: Subarray with sum 0 is from 1 to 4. Subarray with sum 0 is from 5 to 7 Subarray with sum 0 is from 0 to 7To solve this problem, we will check all subarrays possible. And check if the sum of these subarrays is equal to 0 and print them. This ...
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