151. Reverse Words in a String (java)

Author: bluesword12350

solution/0151.Reverse Words in a String/Solution.java

@@ -0,0 +1,19 @@
+class Solution {
+    public String reverseWords(String s) {
+        int length = s.length();
+        if(length ==0)return s;
+        char[] res=new char[length];
+        int len=helper(s.toCharArray(), length -1,res,0,0);
+        return new String(res,0,len);
+    }
+    private int helper(char[] ch,int r,char[] res,int l,int len){
+        while(r>=0&&ch[r]==' ') r--;
+        if(r<0)return Math.max(0,len-1);
+        int rigth=r;
+        while(r>=0&&ch[r]!=' ') r--;
+        len+=rigth-r+1;
+        for(int left=r+1;left<=rigth;left++,l++) res[l] = ch[left];
+        if(l<res.length) res[l++] = ' ';
+        return helper(ch,r,res,l,len);
+    }
+}