Create Add binary strings

Add binary strings

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+//Add binary strings
+
+import java.io.*;
+import java.util.*;
+
+class GFG {
+    public static void main(String args[]) throws IOException {
+        Scanner sc = new Scanner(System.in);
+        int t = sc.nextInt();
+
+        while(t-- > 0) {
+            String a, b;
+            a = sc.next();
+            b = sc.next();
+            Solution ob = new Solution();
+            System.out.println(ob.addBinary(a, b));
+            System.out.println("~");
+        }
+    }
+}
+
+class Solution {
+    public String addBinary(String s1, String s2) {
+        s1 = trimLeadingZeros(s1);
+        s2 = trimLeadingZeros(s2);
+
+        int n = s1.length();
+        int m = s2.length();
+
+        if(n < m) {
+            return addBinary(s2, s1);
+        }
+
+        int j = m - 1;
+        int carry = 0;
+        StringBuilder result = new StringBuilder();
+
+        for(int i = n - 1; i >= 0; i--) {
+            int bit1 = s1.charAt(i) - '0';
+            int sum = bit1 + carry;
+
+            if(j >= 0) {
+                int bit2 = s2.charAt(j) - '0';
+                sum += bit2;
+                j--;
+            }
+
+            int bit = sum % 2;
+            carry = sum / 2;
+
+            result.append((char)(bit + '0'));
+        }
+
+        if(carry > 0) {
+            result.append('1');
+        }
+
+        return result.reverse().toString();
+    }
+
+    static String trimLeadingZeros(String s) {
+        int firstOne = s.indexOf('1');
+
+        return (firstOne == -1) ? "0" : s.substring(firstOne);
+    }
+}