Merge pull request gzc426#109 from MMzhe/patch-2

gzc426 · web-flow · commit a9a231d9c0aa · 2018-11-27T21:41:41.000+08:00
Create sourcema.md
diff --git a/2018.11.28-leetcode151/sourcema.md b/2018.11.28-leetcode151/sourcema.md
@@ -0,0 +1,49 @@
+# LeetCode 151
+    1. public static String reverseWords(String s) {//first method
+        if (s.length() == 0 || s == null) {
+            return s;
+        }
+        String str = s.trim();
+        String[] split = str.split(" +");
+        String result = "";
+        for (int i = split.length - 1; i >=0; i--) {
+            result += split[i] + " ";
+        }
+        return result.substring(0, result.length() - 1);
+    }
+    2. public static String reverseWords2(String s) {//two method
+        if (s.length() == 0 || s == null) {
+            return s;
+        }
+        String str = s.trim();//" "此时str为""
+        char[] chars = str.toCharArray();
+        reverse(chars, 0, chars.length - 1);
+        //String target = new StringBuilder(str).reverse().toString();
+        String result = "";
+        int left=0,right=0;
+       //char[] chars = target.toCharArray();
+        while (right < chars.length) {
+            while (right<chars.length&&chars[right] != ' ') {
+                right++;
+            }
+            reverse(chars, left, right - 1);
+            result+=String.valueOf(Arrays.copyOfRange(chars, left, right))+" ";
+            while (right < chars.length && chars[right] == ' ') {
+                right++;
+            }
+            left=right;
+        }
+        return result.length()==0?result:result.substring(0,result.length()-1);
+    }
+
+      private static void reverse(char[] chars, int i, int j) {
+          while (i < j) {
+              swap(chars, i++, j--);
+          }
+      }
+
+      private static void swap(char[] chars, int i, int j) {
+          char ch = chars[i];
+          chars[i] = chars[j];
+          chars[j] = ch;
+      }
