diff --git a/notes/算法.md b/notes/算法.md
index bc533afd..90a01a29 100644
--- a/notes/算法.md
+++ b/notes/算法.md
@@ -630,18 +630,18 @@ public class MergeSort {
 ### 2. ×Ô¶¥ÏòϹ鲢ÅÅÐò
 
 ```java
-    public static void sort(Comparable[] a) {
-        aux = new Comparable[a.length];
-        sort(a, 0, a.length - 1);
-    }
+public static void sort(Comparable[] a) {
+    aux = new Comparable[a.length];
+    sort(a, 0, a.length - 1);
+}
 
-    private static void sort(Comparable[] a, int lo, int hi) {
-        if (hi <= lo) return;
-        int mid = lo + (hi - lo) / 2;
-        sort(a, lo, mid);
-        sort(a, mid + 1, hi);
-        merge(a, lo, mid, hi);
-    }
+private static void sort(Comparable[] a, int lo, int hi) {
+    if (hi <= lo) return;
+    int mid = lo + (hi - lo) / 2;
+    sort(a, lo, mid);
+    sort(a, mid + 1, hi);
+    merge(a, lo, mid, hi);
+}
 ```
 
 ![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/6468a541-3a9a-4008-82b6-03a0fe941d2a.png)
@@ -659,15 +659,15 @@ public class MergeSort {
 ![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/c7b9b4c8-83d1-4eb0-8408-ea6576a9ed90.png)
 
 ```java
-    public static void busort(Comparable[] a) {
-        int N = a.length;
-        aux = new Comparable[N];
-        for (int sz = 1; sz < N; sz += sz) {
-            for (int lo = 0; lo < N - sz; lo += sz + sz) {
-                merge(a, lo, lo + sz - 1, Math.min(lo + sz + sz - 1, N - 1));
-            }
+public static void busort(Comparable[] a) {
+    int N = a.length;
+    aux = new Comparable[N];
+    for (int sz = 1; sz < N; sz += sz) {
+        for (int lo = 0; lo < N - sz; lo += sz + sz) {
+            merge(a, lo, lo + sz - 1, Math.min(lo + sz + sz - 1, N - 1));
         }
     }
+}
 ```
 
 ## ¿ìËÙÅÅÐò
@@ -701,18 +701,18 @@ public class QuickSort {
 ![](https://github.com/CyC2018/InterviewNotes/blob/master/pics/e198c201-f386-4491-8ad6-f7e433bf992d.png)
 
 ```java
-    private static int partition(Comparable[] a, int lo, int hi) {
-        int i = lo, j = hi + 1;
-        Comparable v = a[lo];
-        while (true) {
-            while (less(a[++i], v)) if (i == hi) break;
-            while (less(v, a[--j])) if (j == lo) break;
-            if (i >= j) break;
-            exch(a, i, j);
-        }
-        exch(a, lo, j);
-        return j;
+private static int partition(Comparable[] a, int lo, int hi) {
+    int i = lo, j = hi + 1;
+    Comparable v = a[lo];
+    while (true) {
+        while (less(a[++i], v)) if (i == hi) break;
+        while (less(v, a[--j])) if (j == lo) break;
+        if (i >= j) break;
+        exch(a, i, j);
     }
+    exch(a, lo, j);
+    return j;
+}
 ```
 
 ### 3. ÐÔÄÜ·ÖÎö
@@ -904,16 +904,16 @@ Java ϵͳ
 ¸ÃËã·¨ÊÇÏßÐÔ¼¶±ðµÄ£¬ÒòΪÿ´ÎÕýºÃ½«Êý×é¶þ·Ö£¬ÄÇô±È½ÏµÄ×Ü´ÎÊýΪ (N+N/2+N/4+..)£¬Ö±µ½ÕÒµ½µÚ k ¸öÔªËØ£¬Õâ¸öºÍÏÔȻСÓÚ 2N¡£
 
 ```java
-    public static Comparable select(Comparable[] a, int k) {
-        int lo = 0, hi = a.length - 1;
-        while (hi > lo) {
-            int j = partion(a, lo, hi);
-            if (j == k) return a[k];
-            else if (j > k) hi = j - 1;
-            else lo = j + 1;
-        }
-        return a[k];
+public static Comparable select(Comparable[] a, int k) {
+    int lo = 0, hi = a.length - 1;
+    while (hi > lo) {
+        int j = partion(a, lo, hi);
+        if (j == k) return a[k];
+        else if (j > k) hi = j - 1;
+        else lo = j + 1;
     }
+    return a[k];
+}
 ```
 
 # µÚÈýÕ ²éÕÒ