Update 5. 替换空格.md

notes/5. 替换空格.md

@@ -51,7 +51,54 @@ public String replaceSpace(StringBuffer str) {
 }
 ```
 
+```java
+class Solution {
+    public String replaceSpace(String s) {
+        return replaceSB2(s);
+    }
+    public String replaceAll(String s){
+        return s.replaceAll(" ", "%20");
+    }
+    public String replaceSB2(String s){
+        StringBuilder sb = new StringBuilder();
+        for( int i = 0; i < s.length(); i++){
+            if(s.charAt(i) == ' '){
+                sb.append("%20");
+            }else{
+                sb.append(s.charAt(i));
 
+            }
+        }
+        return sb.toString();
+    }
+    public String replaceSB(String s){
+        StringBuilder sb = new StringBuilder(s);
+
+        for( int i = 0; i < s.length(); i++){
+            if(s.charAt(i) == ' '){
+                sb.append("==");
+            }
+        }
+
+        int i = s.length()-1;
+        int j = sb.length()-1;
+        while(i<j && i >=0){
+            if(sb.charAt(i) == ' '){
+                sb.setCharAt(j--,'0');
+                sb.setCharAt(j--,'2');
+                sb.setCharAt(j--,'%');
+            }else{
+                sb.setCharAt(j--,sb.charAt(i));
+            }
+
+            i--;
+        }
+        return sb.toString();
+
+    }
+}
+
+```