Bitwise OR of N binary strings - GeeksforGeeks

14 Jun, 2021
Given an array arr[] of binary strings, the task is to calculate the bitwise OR of all of these strings and print the resultant string.Examples:  
Input: arr[] = {“100”, “1001”, “0011”} Output 1111 0100 OR 1001 OR 0011 = 1111Input: arr[] = {“10”, “11”, “1000001”} Output: 1000011  
 
Approach: We can do this by first finding the maximum sized string. We need this since we have to add 0s at the front of the strings whose lengths are less than max size. Then apply OR operation on each bit. For example, if strings are “100”, “001” and “1111”. Here max size is 4, so we have to add 1 zero on first and second string to make their length 4 and then the OR operation can be performed on each of the bits of the numbers resulting in “0100” OR “0001” OR “1111” = “1111”.Below is the implementation of the above approach: 
C++
Java
Python3
C#
Javascript
// C++ implementation of the approach#include <bits/stdc++.h>using namespace std; // Function to return the bitwise OR of// all the binary stringsstring strBitwiseOR(string* arr, int n){    string res;     int max_size = INT_MIN;     // Get max size and reverse each string    // Since we have to perform OR operation    // on bits from right to left    // Reversing the string will make it easier    // to perform operation from left to right    for (int i = 0; i < n; i++) {        max_size = max(max_size, (int)arr[i].size());        reverse(arr[i].begin(), arr[i].end());    }     for (int i = 0; i < n; i++) {         // Add 0s to the end of strings        // if needed        string s;        for (int j = 0; j < max_size - arr[i].size(); j++)            s += '0';         arr[i] = arr[i] + s;    }     // Perform OR operation on each bit    for (int i = 0; i < max_size; i++) {        int curr_bit = 0;        for (int j = 0; j < n; j++)            curr_bit = curr_bit | (arr[j][i] - '0');         res += (curr_bit + '0');    }     // Reverse the resultant string    // to get the final string    reverse(res.begin(), res.end());     // Return the final string    return res;} // Driver codeint main(){    string arr[] = { "10", "11", "1000001" };    int n = sizeof(arr) / sizeof(arr[0]);    cout << strBitwiseOR(arr, n);     return 0;}
// Java implementation of the approach class GFG{ // Function to return the bitwise OR of// all the binary stringsstatic String strBitwiseOR(String[] arr, int n){    String res="";     int max_size = Integer.MIN_VALUE;     // Get max size and reverse each string    // Since we have to perform OR operation    // on bits from right to left    // Reversing the string will make it easier    // to perform operation from left to right    for (int i = 0; i < n; i++)    {        max_size = Math.max(max_size, (int)arr[i].length());        arr[i] = reverse(arr[i]);    }     for (int i = 0; i < n; i++)    {         // Add 0s to the end of strings        // if needed        String s="";        for (int j = 0; j < max_size - arr[i].length(); j++)            s += '0';         arr[i] = arr[i] + s;    }         // Perform OR operation on each bit    for (int i = 0; i < max_size; i++)    {        int curr_bit = 0;        for (int j = 0; j < n; j++)            curr_bit = curr_bit | (arr[j].charAt(i) - '0');         res += (char)(curr_bit + '0');    }     // Reverse the resultant string    // to get the final string    res = reverse(res);     // Return the final string    return res;} static String reverse(String input){    char[] temparray = input.toCharArray();    int left, right = 0;    right = temparray.length - 1;     for (left = 0; left < right; left++, right--)    {        // Swap values of left and right        char temp = temparray[left];        temparray[left] = temparray[right];        temparray[right] = temp;    }    return String.valueOf(temparray);}     // Driver codepublic static void main(String[] args){    String arr[] = { "10", "11", "1000001" };    int n = arr.length;    System.out.println(strBitwiseOR(arr, n));}} // This code contributed by Rajput-Ji
# Python3 implementation of the approach # Function to return the bitwise OR of# all the binary stringsdef strBitwiseOR(arr, n):    res=""    max_size = -(2**32)         # Get max size and reverse each string    # Since we have to perform OR operation    # on bits from right to left    # Reversing the string will make it easier    # to perform operation from left to right    for i in range(n):        max_size = max(max_size, len(arr[i]))        arr[i] = arr[i][::-1]         for i in range(n):                 # Add 0s to the end of strings        # if needed        s = ""        for j in range(max_size - len(arr[i])):            s += '0'                 arr[i] = arr[i] + s             # Perform OR operation on each bit    for i in range(max_size):        curr_bit = 0        for j in range(n):            curr_bit = curr_bit | ord(arr[j][i])                 res += chr(curr_bit)         # Reverse the resultant string    # to get the final string    res=res[::-1]     # Return the final string    return res  # Driver codearr = ["10", "11", "1000001"]n = len(arr)print(strBitwiseOR(arr, n)) # This code is contributed by shubhamsingh10
// C# implementation of the approachusing System; class GFG{  // Function to return the bitwise OR of// all the binary stringsstatic String strBitwiseOR(String[] arr, int n){    String res="";      int max_size = int.MinValue;      // Get max size and reverse each string    // Since we have to perform OR operation    // on bits from right to left    // Reversing the string will make it easier    // to perform operation from left to right    for (int i = 0; i < n; i++)    {        max_size = Math.Max(max_size, (int)arr[i].Length);        arr[i] = reverse(arr[i]);    }      for (int i = 0; i < n; i++)    {          // Add 0s to the end of strings        // if needed        String s="";        for (int j = 0; j < max_size - arr[i].Length; j++)            s += '0';          arr[i] = arr[i] + s;    }          // Perform OR operation on each bit    for (int i = 0; i < max_size; i++)    {        int curr_bit = 0;        for (int j = 0; j < n; j++)            curr_bit = curr_bit | (arr[j][i] - '0');          res += (char)(curr_bit + '0');    }      // Reverse the resultant string    // to get the final string    res = reverse(res);      // Return the final string    return res;}  static String reverse(String input){    char[] temparray = input.ToCharArray();    int left, right = 0;    right = temparray.Length - 1;      for (left = 0; left < right; left++, right--)    {        // Swap values of left and right        char temp = temparray[left];        temparray[left] = temparray[right];        temparray[right] = temp;    }    return String.Join("",temparray);}      // Driver codepublic static void Main(String[] args){    String []arr = { "10", "11", "1000001" };    int n = arr.Length;    Console.WriteLine(strBitwiseOR(arr, n));}} /* This code contributed by PrinciRaj1992 */
<script> // JavaScript implementation of the approach // Function to return the bitwise OR of// all the binary stringsfunction strBitwiseOR(arr, n){    var res = "";     var max_size = -1000000000;     // Get max size and reverse each string    // Since we have to perform OR operation    // on bits from right to left    // Reversing the string will make it easier    // to perform operation from left to right    for (var i = 0; i < n; i++) {        max_size = Math.max(max_size, arr[i].length);        arr[i] = arr[i].split('').reverse().join('');    }     for (var i = 0; i < n; i++) {         // Add 0s to the end of strings        // if needed        var s = "";        for (var j = 0; j < max_size - arr[i].length; j++)            s += '0';         arr[i] = arr[i] + s;    }     // Perform OR operation on each bit    for (var i = 0; i < max_size; i++) {        var curr_bit = 0;        for (var j = 0; j < n; j++)            curr_bit = curr_bit | (arr[j][i].charCodeAt(0) -            '0'.charCodeAt(0));         res += String.fromCharCode(curr_bit + '0'.charCodeAt(0));    }     // Reverse the resultant string    // to get the final string    res = res.split('').reverse().join('');     // Return the final string    return res;} // Driver code var arr = ["10", "11", "1000001"];var n = arr.length;document.write( strBitwiseOR(arr, n));  </script>
1000011
 
Rajput-Ji
princiraj1992
SHUBHAMSINGH10
rrrtnx
Bitwise-OR
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Greedy Algorithms
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