docs: update the whole repository

* fix some bugs
* delete duplicate files
* format code

Others/CRC32.java

@@ -0,0 +1,31 @@
+package Others;
+
+import java.util.BitSet;
+
+/**
+ * Generates a crc32 checksum for a given string or byte array
+ */
+public class CRC32 {
+
+    public static void main(String[] args) {
+        System.out.println(Integer.toHexString(crc32("Hello World")));
+    }
+
+    public static int crc32(String str) {
+        return crc32(str.getBytes());
+    }
+
+    public static int crc32(byte[] data) {
+        BitSet bitSet = BitSet.valueOf(data);
+        int crc32 = 0xFFFFFFFF; // initial value
+        for (int i = 0; i < data.length * 8; i++) {
+            if (((crc32 >>> 31) & 1) != (bitSet.get(i) ? 1 : 0))
+                crc32 = (crc32 << 1) ^ 0x04C11DB7; // xor with polynomial
+            else
+                crc32 = (crc32 << 1);
+        }
+        crc32 = Integer.reverse(crc32); // result reflect
+        return crc32 ^ 0xFFFFFFFF; // final xor value
+    }
+
+}