Find i’th Index character in a binary string obtained after n iterations
Last Updated :
08 Dec, 2023
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Given a decimal number m, convert it into a binary string and apply n iterations. In each iteration, 0 becomes “01” and 1 becomes “10”. Find the (based on indexing) index character in the string after the nth iteration.
Examples:
Input : m = 5, n = 2, i = 3
Output : 1
Input : m = 3, n = 3, i = 6
Output : 1
Recommended: Please solve it on “PRACTICE” first, before moving on to the solution.
- Change a decimal number into a binary and store it in string s.
- Run loop n times in each iteration. Run another loop of string length s to convert 0 to “01” and 1 to “10” and store in another string s1. After completion of each iteration, assign string s1 to s.
- Finally, return the value of the ith index in string s.
Implementation:
C++
// C++ Program to find ith character in // a binary string.#include <bits/stdc++.h>using namespace std;// Function to store binary Representationvoid binary_conversion(string &s, int m) { while (m) { int tmp = m % 2; s += tmp + '0'; m = m / 2; } reverse(s.begin(), s.end());}// Function to find ith characterint find_character(int n, int m, int i) { string s; // Function to change decimal to binary binary_conversion(s, m); string s1 = ""; for (int x = 0; x < n; x++) { for (int y = 0; y < s.length(); y++) { if (s[y] == '1') s1 += "10"; else s1 += "01"; } // Assign s1 string in s string s = s1; s1 = ""; } return s[i] - '0';}// Driver Functionint main() { int m = 5, n = 2, i = 8; cout << find_character(n, m, i); return 0;} |
Java
// Java Program to find ith // character in a binary String.import java.io.*;import java.util.Arrays;class GFG{static String s = "";static String ReverseString(String s){ char[] arr = s.toCharArray(); for(int i = 0; i < arr.length / 2; i++) { char temp = arr[i]; arr[i] = arr[arr.length - i -1]; arr[arr.length - i - 1] = temp; } return new String(arr);}// Function to store// binary Representationstatic void binary_conversion(int m) { while (m != 0) { int tmp = m % 2; s += Integer.toString(tmp); m = (int)(m / 2); } s = ReverseString(s);}// Function to find // ith characterstatic int find_character(int n, int m, int i) { // Function to change // decimal to binary binary_conversion(m); String s1 = ""; for (int x = 0; x < n; x++) { for (int y = 0; y < s.length(); y++) { if (s.charAt(y) == '1') s1 += "10"; else s1 += "01"; } // Assign s1 String // in s String s = s1; s1 = ""; } return s.charAt(i) - '0';}// Driver Codepublic static void main(String args[]){ int m = 5, n = 2, i = 8; System.out.print( find_character(n, m, i));}}// This code is contributed by // Manish Shaw(manishshaw1) |
Python3
# Python3 Program to find ith character in # a binary string.# Function to store binary Representationdef binary_conversion(s, m): while(m): temp = m % 2 s += str(temp) m = m // 2 return s[::-1]# Function to find ith characterdef find_character(n, m, i): s = ""# Function to change decimal to binary s = binary_conversion(s, m) s1 = "" for x in range(n): for j in range(len(s)): if s[j] == "1": s1 += "10" else: s1 += "01" # Assign s1 string in s string s = s1 s1 = "" e = ord(s[i]) r = ord('0') return e-r# Driver codem, n, i = 5, 2, 8print(find_character(n,m,i))# This code is contributed by mohit kumar 29 |
C#
// C# Program to find ith // character in a binary string.using System;class GFG{ static string ReverseString(string s) { char[] arr = s.ToCharArray(); Array.Reverse(arr); return new string(arr); } // Function to store // binary Representation static void binary_conversion(ref string s, int m) { while (m != 0) { int tmp = m % 2; s += tmp.ToString(); m = (int)(m / 2); } s = ReverseString(s); } // Function to find // ith character static int find_character(int n, int m, int i) { string s = ""; // Function to change // decimal to binary binary_conversion(ref s, m); string s1 = ""; for (int x = 0; x < n; x++) { for (int y = 0; y < s.Length; y++) { if (s[y] == '1') s1 += "10"; else s1 += "01"; } // Assign s1 string // in s string s = s1; s1 = ""; } return s[i] - '0'; } // Driver Code static void Main() { int m = 5, n = 2, i = 8; Console.Write(find_character(n, m, i)); }}// This code is contributed by // Manish Shaw(manishshaw1) |
Javascript
<script>// Javascript Program to find ith // character in a binary String.let s = "";function ReverseString(s){ let arr = s.split(""); for(let i = 0; i < arr.length / 2; i++) { let temp = arr[i]; arr[i] = arr[arr.length - i -1]; arr[arr.length - i - 1] = temp; } return arr.join("");}// Function to store// binary Representationfunction binary_conversion(m){ while (m != 0) { let tmp = m % 2; s += tmp.toString(); m = Math.floor(m / 2); } s = ReverseString(s);}// Function to find // ith characterfunction find_character(n,m,i){ // Function to change // decimal to binary binary_conversion(m); let s1 = ""; for (let x = 0; x < n; x++) { for (let y = 0; y < s.length; y++) { if (s[y] == '1') s1 += "10"; else s1 += "01"; } // Assign s1 String // in s String s = s1; s1 = ""; } return s[i] - '0';}// Driver Codelet m = 5, n = 2, i = 8;document.write(find_character(n, m, i));// This code is contributed by patel2127</script> |
PHP
<?php// Function to store binary Representationfunction binaryConversion($s, $m) { while ($m) { $temp = $m % 2; $s .= strval($temp); $m = (int)($m / 2); } return strrev($s);}// Function to find ith characterfunction findCharacter($n, $m, $i) { $s = ""; // Function to change decimal to binary $s = binaryConversion($s, $m); $s1 = ""; for ($x = 0; $x < $n; $x++) { for ($j = 0; $j < strlen($s); $j++) { if ($s[$j] == "1") { $s1 .= "10"; } else { $s1 .= "01"; } } // Assign s1 string to s string $s = $s1; $s1 = ""; } $e = ord($s[$i]); $r = ord('0'); return $e - $r;}// Driver code$m = 5;$n = 2;$i = 8;echo findCharacter($n, $m, $i);?> |
Output
1
Time complexity : O(|S|*2^n)
Auxiliary Space : O(n)
Refer Set-2 for an optimized solution.
