Added Add Binary

Author: gahogg

Add Binary - Leetcode 67/Add Binary - Leetcode 67.cpp

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+class BigInt {
+private:
+    string binary;
+
+    // Helper function to ensure strings are the same length
+    static void equalizeLength(string& a, string& b) {
+        int lengthDifference = a.size() - b.size();
+        if (lengthDifference > 0)
+            b.insert(0, lengthDifference, '0');
+        else
+            a.insert(0, -lengthDifference, '0');
+    }
+
+    // Helper function to remove leading zeros
+    void removeLeadingZeros() {
+        // Erase leading zeros while keeping at least one zero if the number is
+        // zero
+        auto firstNonZero = binary.find_first_not_of('0');
+        if (firstNonZero != string::npos) {
+            binary.erase(0, firstNonZero);
+        } else {
+            binary =
+                "0";  // Adjust to maintain a minimum representation of zero
+        }
+    }
+
+public:
+    BigInt() : binary("0") {}
+
+    // Constructor from a binary string
+    BigInt(const string& bin) : binary(bin) { removeLeadingZeros(); }
+
+    // Bitwise XOR
+    BigInt operator^(const BigInt& other) const {
+        string a = binary;
+        string b = other.binary;
+        equalizeLength(a, b);
+        string result;
+        for (size_t i = 0; i < a.size(); i++) {
+            char xorChar = (a[i] == b[i] ? '0' : '1');
+            result.push_back(xorChar);
+        }
+        return BigInt(result);
+    }
+
+    // Bitwise AND
+    BigInt operator&(const BigInt& other) const {
+        string a = binary;
+        string b = other.binary;
+        equalizeLength(a, b);
+        string result;
+        for (size_t i = 0; i < a.size(); i++) {
+            char andChar = (a[i] == '1' && b[i] == '1' ? '1' : '0');
+            result.push_back(andChar);
+        }
+        return BigInt(result);
+    }
+
+    // Left shift
+    BigInt operator<<(int shift) const {
+        string result = binary;
+        result.append(shift, '0');
+        return BigInt(result);
+    }
+
+    // Check if BigInt is zero
+    bool isZero() const {
+        for (char c : binary)
+            if (c != '0') return false;
+        return true;
+    }
+
+    // Getter for binary string
+    string getBinary() const { return binary; }
+};
+
+class Solution {
+public:
+    string addBinary(string a, string b) {
+        BigInt x(a);
+        BigInt y(b);
+        BigInt carry, answer;
+
+        while (!y.isZero()) {
+            answer = x ^ y;
+            carry = (x & y) << 1;
+            x = answer;
+            y = carry;
+        }
+        return x.getBinary();
+    }
+};

Add Binary - Leetcode 67/Add Binary - Leetcode 67.java

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+import java.math.BigInteger;
+
+public class Solution {
+    public String addBinary(String a, String b) {
+        BigInteger x = new BigInteger(a, 2);
+        BigInteger y = new BigInteger(b, 2);
+
+        while (y.compareTo(BigInteger.ZERO) != 0) {
+            BigInteger answer = x.xor(y);
+            BigInteger carry = x.and(y).shiftLeft(1);
+            x = answer;
+            y = carry;
+        }
+
+        return x.toString(2);
+    }
+}

Add Binary - Leetcode 67/Add Binary - Leetcode 67.js

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+var addBinary = function(a, b) {
+    let x = BigInt("0b" + a);
+    let y = BigInt("0b" + b);
+
+    while (y !== 0n) {
+        let answer = x ^ y;
+        let carry = (x & y) << 1n;
+        x = answer;
+        y = carry;
+    }
+
+    return x.toString(2);
+};

Add Binary - Leetcode 67/Add Binary - Leetcode 67.py

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+class Solution:
+    def addBinary(self, a, b) -> str:
+        x, y = int(a, 2), int(b, 2)
+        
+        while y:
+            answer = x ^ y
+            carry = (x & y) << 1
+            x, y = answer, carry
+            
+        return bin(x)[2:]
+        # Time: O(A + B)
+        # Space: O(max(A, B))