Given a string S consisting of space-separated integers, the task is to extract the Kth number present in the string.
Note: The string contains at least K numbers in it.
Examples:
Input: S = “12 13 15”, K= 3
Output: 15
Explanation: The 3rd integer in the above string is 15.Input: S = “10 20 30 40”, K = 2
Output: 20
Explanation: The 2nd integer in the above string is 20.
Naive Approach: The simplest approach to solve the problem is to traverse the string and keep a count of spaces encountered. Once, K – 1 spaces are encountered, print the number up to the next space as the required answer.
Below is the implementation of the above approach:
C++
// C++ Program for the above approach#include <iostream>using namespace std;// Function to print kth integer// in a given stringvoid print_kth_string(string s, int K){ // Size of the string int N = s.length(); // Pointer for iteration int i; for (i = 0; i < N; i++) { // If space char found // decrement K if (s[i] == ' ') K--; // If K becomes 1, the next // string is the required one if (K == 1) break; } // Print the required number while (i++ < N && s[i] != ' ') cout << s[i];}// Driver Codeint main(){ // Given string string s("10 20 30 40"); // Given K int K = 4; // Function call print_kth_string(s, K);} |
Java
// Java program for the above approachimport java.io.*;class GFG{ // Function to print kth integer// in a given stringstatic void print_kth_string(String s, int K){ // Size of the string int N = s.length(); // Pointer for iteration int i; for(i = 0; i < N; i++) { // If space char found // decrement K if (s.charAt(i) == ' ') K--; // If K becomes 1, the next // string is the required one if (K == 1) break; } // Print the required number while (i++ < N - 1 && s.charAt(i) != ' ') System.out.print(s.charAt(i));} // Driver Codepublic static void main (String[] args){ // Given string String s = "10 20 30 40"; // Given K int K = 4; // Function call print_kth_string(s, K);}}// This code is contributed by sanjoy_62 |
Python3
# Python3 program for # the above approach# Function to print kth integer# in a given stringdef print_kth_string(s, K): # Size of the string N = len(s); for i in range(0, N, 1): # If space char found # decrement K if (s[i] == ' '): K -= 1; # If K becomes 1, the next # string is the required one if (K == 1): break; # Print required number while (i < N): if(s[i] != ' '): print(s[i], end = ""); i += 1;# Driver Codeif __name__ == '__main__': # Given string s = "10 20 30 40"; # Given K K = 4; # Function call print_kth_string(s, K);# This code is contributed by Rajput-Ji |
C#
// C# program for the above approach using System;class GFG{ // Function to print kth integer// in a given stringstatic void print_kth_string(string s, int K){ // Size of the string int N = s.Length; // Pointer for iteration int i; for(i = 0; i < N; i++) { // If space char found // decrement K if (s[i] == ' ') K--; // If K becomes 1, the next // string is the required one if (K == 1) break; } // Print the required number while (i++ < N - 1 && s[i] != ' ') Console.Write(s[i]);} // Driver Codepublic static void Main (){ // Given string string s = "10 20 30 40"; // Given K int K = 4; // Function call print_kth_string(s, K);}}// This code is contributed by sanjoy_62 |
Javascript
<script>// javascript program for the above approach // Function to print kth integer // in a given string function print_kth_string( s , K) { // Size of the string var N = s.length; // Pointer for iteration var i; for (i = 0; i < N; i++) { // If space char found // decrement K if (s.charAt(i) == ' ') K--; // If K becomes 1, the next // string is the required one if (K == 1) break; } // Print the required number while (i++ < N - 1 && s.charAt(i) != ' ') document.write(s.charAt(i)); } // Driver Code // Given string var s = "10 20 30 40"; // Given K var K = 4; // Function call print_kth_string(s, K);// This code is contributed by umadevi9616 </script> |
Output:
40
Time Complexity: O(N), where N is the length of the string.
Auxiliary Space: O(1)
Stringstream Approach: The idea is to use stringstream in C++ which associates a string object with a stream and allowing us to read from the string as if it were a stream (like cin).
Below is the implementation of the above approach:
C++
// C++ program for the above approach#include <bits/stdc++.h>using namespace std;// Function to print Kth integer// from a given stringvoid print_kth_string(string str, int K){ // Split input into words // using stringstream stringstream iss(str); // Stores individual words string kth; // Extract words from stream while (iss >> kth && K) { K--; // If kth position // is reached if (K == 0) { cout << kth; break; } }}// Driver Codeint main(){ // Given string string s("10 20 30 40"); // Given K int K = 4; // Function call print_kth_string(s, K);} |
Java
// Java program for // the above approachimport java.util.*;class GFG{// Function to print Kth integer// from a given Stringstatic void print_kth_String(String str, int K) { // Split input into words // using split String[] iss = str.split(" "); K--; System.out.print(iss[K]);}// Driver Codepublic static void main(String[] args) { // Given String String s = ("10 20 30 40"); // Given K int K = 4; // Function call print_kth_String(s, K);}}// This code is contributed by Rajput-Ji |
Python3
# Python3 program for the above approach# Function to print Kth integer# from a given stringdef print_kth_string(str1, K): # Split input into words # using stringstream st = str1.split(" ") # Stores individual words print(st[K - 1])# Driver Codeif __name__ == '__main__': # Given string s = "10 20 30 40" # Given K K = 4 # Function call print_kth_string(s, K)# This code is contributed by SURENDRA_GANGWAR |
C#
// C# program for // the above approachusing System;class GFG{// Function to print Kth integer// from a given Stringstatic void print_kth_String(String str, int K) { // Split input into words // using split String[] iss = str.Split(' '); K--; Console.Write(iss[K]);}// Driver Codepublic static void Main(String[] args) { // Given String String s = ("10 20 30 40"); // Given K int K = 4; // Function call print_kth_String(s, K);}}// This code is contributed by Rajput-Ji |
Javascript
// Function to print Kth integer from a given stringfunction print_kth_String(str, K) { // Split input into words using split let iss = str.split(" "); K--; console.log(iss[K]);}// Driver Codelet s = "10 20 30 40";let K = 4;// Function callprint_kth_String(s, K); |
Output
40
Time Complexity: O(N), where N is the length of the string.
Auxiliary Space: O(1)
Built-in String Functions based Approach: The idea is to use strtok() function to extract the string at the key. Use c_str() function to get the char pointer reference of an array of the characters.
Below is the implementation of the above approach:
C++
// C++ program of the above approach#include <cstring>#include <iostream>using namespace std;// Function to extract integer at key// position in the given stringvoid print_kth_string(string str, int K){ // strtok(): Extracts the number at key // c_str(): Type cast string to char* char* s = strtok((char*)str.c_str(), " "); while (K > 1) { // Get the token at position -> key s = strtok(NULL, " "); K--; } // Print the kth integer cout << string(s) << " ";}// Driver Codeint main(){ // Given string string s("10 20 30 40"); // Given K int K = 2; // Function call print_kth_string(s, K); return 0;} |
Java
// Java program of the // above approachimport java.util.*;class GFG{// Function to extract integer // at key position in the given Stringstatic void print_kth_String(String str, int K){ // StringTokenizer(): Extracts // the number at key // c_str(): Type cast // String to char* StringTokenizer st = new StringTokenizer(str); int count = 1; while (st.hasMoreTokens() && K > 0 ) { if(count == K) System.out.println(st.nextToken()); count++; st.nextToken(); }}// Driver Codepublic static void main(String[] args){ // Given String String s = ("10 20 30 40"); // Given K int K = 2; // Function call print_kth_String(s, K);}}// This code is contributed by 29AjayKumar |
Python3
# Python code of the above approachimport re# Function to extract integer at key# position in the given stringdef print_kth_string(string, K): # split the string using space as a separator s = re.split(" ", string) # return the Kth element of the split string return s[K-1]# Driver Codeif __name__ == '__main__': # Given string s = "10 20 30 40" # Given K K = 2 # Function call print(print_kth_string(s, K)) |
C#
// C# program of the // above approachusing System;class GFG{// Function to extract integer // at key position in the given Stringstatic void print_kth_String(String str, int K){ // StringTokenizer(): Extracts // the number at key // c_str(): Type cast // String to char* String[] iss = str.Split(' '); K--; Console.Write(iss[K]);}// Driver Codepublic static void Main(String[] args){ // Given String String s = ("10 20 30 40"); // Given K int K = 2; // Function call print_kth_String(s, K);}}// This code is contributed by Rajput-Ji |
Javascript
// Function to extract integer at key position in the given stringfunction print_kth_string(str, K) { // Split input string into words using split let words = str.split(" "); // Print the Kth integer console.log(words[K-1]);}// Driver Codelet s = "10 20 30 40";let K = 2;// Function callprint_kth_string(s, K); |
Output
20
Time Complexity: O(N), where N is the length of the string.
Auxiliary Space: O(1)
Feeling lost in the world of random DSA topics, wasting time without progress? It’s time for a change! Join our DSA course, where we’ll guide you on an exciting journey to master DSA efficiently and on schedule.
Ready to dive in? Explore our Free Demo Content and join our DSA course, trusted by over 100,000 neveropen!
Ready to dive in? Explore our Free Demo Content and join our DSA course, trusted by over 100,000 neveropen!
