diff --git a/README.md b/README.md
index fb49d0501a9ec495209c86e9b9fac1ab7b87a815..4ad05ea19be49963487caca50113b26a5384379a 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,8 @@
 
 [链表K个节点的组内逆序调整问题](https://www.cnblogs.com/greyzeng/p/17859529.html)
 
+[位图的使用与实现](https://www.cnblogs.com/greyzeng/p/16634282.html)
+
 ## 更多
 
 [算法和数据结构学习笔记：CSDN](https://blog.csdn.net/hotonyhui/category_1250716.html)
@@ -30,8 +32,6 @@
 
 [算法和数据结构学习代码: Github](https://github.com/GreyZeng/algorithm)
 
-[算法和数据结构学习代码: GitCode](https://gitcode.net/hotonyhui/algorithm)
-
 ## 参考资料
 
 [算法和数据结构基础班-左程云](https://ke.qq.com/course/2145184)
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diff --git a/src/main/java/git/snippet/bit/BitMap.java b/src/main/java/git/snippet/bit/BitMap.java
new file mode 100644
index 0000000000000000000000000000000000000000..f08fae8b1f95c241832add1232dd3ceb0fc815de
--- /dev/null
+++ b/src/main/java/git/snippet/bit/BitMap.java
@@ -0,0 +1,36 @@
+package git.snippet.bit;
+
+import java.util.HashSet;
+import java.util.Set;
+
+// 位图
+// 笔记：https://www.cnblogs.com/greyzeng/p/16634282.html
+
+// 位图
+public class BitMap {
+
+    private final long[] bits;
+
+    // 初始化
+    public BitMap(int max) {
+        // 准备多少个整数？ 0 ~ 63 需要1个整数
+        // >> 6 就是 除以 64 >> 效率比除法高
+        bits = new long[(max + 64) >> 6];
+    }
+
+    public void add(int num) {
+        // bits[num / 64] |= (1L << (num % 64));
+        // num % 64 ---> num & 63 即：0b111111
+        // 只适用于 2 的 n 次方
+        // 注意：这里是1L非1，如果是1，因为要管64位
+        bits[num >> 6] |= (1L << (num & 0b111111));
+    }
+
+    public void remove(int num) {
+        bits[num >> 6] &= ~(1L << (num & 0b111111));
+    }
+
+    public boolean contains(int num) {
+        return (bits[num >> 6] & (1L << (num & 0b111111))) != 0;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/git/snippet/bit/Code_BitMap.java b/src/main/java/git/snippet/bit/Code_BitMap.java
deleted file mode 100644
index cdc82763213660253537baf4298ed3b476ed7db6..0000000000000000000000000000000000000000
--- a/src/main/java/git/snippet/bit/Code_BitMap.java
+++ /dev/null
@@ -1,68 +0,0 @@
-package git.snippet.bit;
-
-import java.util.HashSet;
-import java.util.Set;
-
-// 位图
-// 笔记：https://www.cnblogs.com/greyzeng/p/16634282.html
-public class Code_BitMap {
-
-    public static void main(String[] args) {
-        System.out.println("test begin");
-        int max = 70000;
-        BitMap bitMap = new BitMap(max);
-        Set<Integer> set = new HashSet<>();
-        int testTime = 90000000;
-        for (int i = 0; i < testTime; i++) {
-            int num = (int) (Math.random() * (max + 1));
-            double decide = Math.random();
-            if (decide < 0.333) {
-                bitMap.add(num);
-                set.add(num);
-            } else if (decide < 0.666) {
-                bitMap.remove(num);
-                set.remove(num);
-            } else {
-                if (bitMap.contains(num) != set.contains(num)) {
-                    System.out.println("Oops!");
-                    break;
-                }
-            }
-        }
-        for (int num = 0; num <= max; num++) {
-            if (bitMap.contains(num) != set.contains(num)) {
-                System.out.println("Oops!");
-            }
-        }
-        System.out.println("test end");
-    }
-
-    // 位图
-    public static class BitMap {
-
-        private final long[] bits;
-
-        // 初始化
-        public BitMap(int max) {
-            // 准备多少个整数？ 0 ~ 63 需要1个整数
-            // >> 6 就是 除以 64 >> 效率比除法高
-            bits = new long[(max + 64) >> 6];
-        }
-
-        public void add(int num) {
-            // bits[num / 64] |= (1L << (num % 64));
-            // num % 64 ---> num & 63 即：0b111111
-            // 只适用于 2 的 n 次方
-            // 注意：这里是1L非1，如果是1，因为要管64位
-            bits[num >> 6] |= (1L << (num & 0b111111));
-        }
-
-        public void remove(int num) {
-            bits[num >> 6] &= ~(1L << (num & 0b111111));
-        }
-
-        public boolean contains(int num) {
-            return (bits[num >> 6] & (1L << (num & 0b111111))) != 0;
-        }
-    }
-}
diff --git a/src/test/java/git/snippet/bit/BitMapTest.java b/src/test/java/git/snippet/bit/BitMapTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..e62f7bc8af94fd08f606716e0e67d8b27e31033d
--- /dev/null
+++ b/src/test/java/git/snippet/bit/BitMapTest.java
@@ -0,0 +1,37 @@
+package git.snippet.bit;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+@DisplayName("位图测试")
+public class BitMapTest {
+    @Test
+    void testBitMap() {
+        // System.out.println("test begin");
+        int max = 70000;
+        BitMap bitMap = new BitMap(max);
+        Set<Integer> set = new HashSet<>();
+        int testTime = 90000000;
+        for (int i = 0; i < testTime; i++) {
+            int num = (int) (Math.random() * (max + 1));
+            double decide = Math.random();
+            if (decide < 0.333) {
+                bitMap.add(num);
+                set.add(num);
+            } else if (decide < 0.666) {
+                bitMap.remove(num);
+                set.remove(num);
+            } else {
+                assertEquals(bitMap.contains(num), set.contains(num));
+            }
+        }
+        for (int num = 0; num <= max; num++) {
+            assertEquals(bitMap.contains(num), set.contains(num));
+        }
+    }
+}
\ No newline at end of file