add a solution for 151

fishercoder1534 · fishercoder1534 · commit 22c8dd12821f · 2021-10-20T07:55:55.000-07:00
diff --git a/src/main/java/com/fishercoder/solutions/_151.java b/src/main/java/com/fishercoder/solutions/_151.java
@@ -24,7 +24,7 @@ public String reverseWords(String s) {
             while (!stack.isEmpty()) {
                 stringBuilder.append(stack.pollLast()).append(" ");
             }
-            return stringBuilder.substring(0, stringBuilder.length() - 1).toString();
+            return stringBuilder.substring(0, stringBuilder.length() - 1);
         }
     }
 
@@ -61,4 +61,44 @@ public String reverseWords(String s) {
             return result;
         }
     }
+
+    public static class Solution3 {
+        public String reverseWords(String s) {
+            s = s.trim();
+            StringBuilder sb = new StringBuilder();
+            for (int i = 0; i < s.length(); i++) {
+                if (s.charAt(i) == ' ' && sb.length() > 0 && sb.charAt(sb.length() - 1) == ' ') {
+                    continue;
+                } else {
+                    sb.append(s.charAt(i));
+                }
+            }
+            int left = 0;
+            int right = sb.length() - 1;
+            while (left < right) {
+                char tmp = sb.charAt(left);
+                sb.setCharAt(left, sb.charAt(right));
+                sb.setCharAt(right, tmp);
+                left++;
+                right--;
+            }
+            int boundary = 0;
+            while (boundary < sb.length()) {
+                left = boundary;
+                while (boundary < sb.length() && sb.charAt(boundary) != ' ') {
+                    boundary++;
+                }
+                right = boundary - 1;
+                while (left < right) {
+                    char tmp = sb.charAt(left);
+                    sb.setCharAt(left, sb.charAt(right));
+                    sb.setCharAt(right, tmp);
+                    left++;
+                    right--;
+                }
+                boundary++;
+            }
+            return sb.toString();
+        }
+    }
 }
diff --git a/src/test/java/com/fishercoder/_151Test.java b/src/test/java/com/fishercoder/_151Test.java
@@ -9,12 +9,14 @@
 public class _151Test {
     private static _151.Solution1 solution1;
     private static _151.Solution2 solution2;
+    private static _151.Solution3 solution3;
     private static String s;
 
     @BeforeClass
     public static void setup() {
         solution1 = new _151.Solution1();
         solution2 = new _151.Solution2();
+        solution3 = new _151.Solution3();
     }
 
     @Test
@@ -45,5 +47,13 @@ public void test4() {
     public void test5() {
         s = "  hello world  ";
         assertEquals("world hello", solution2.reverseWords(s));
+        assertEquals("world hello", solution3.reverseWords(s));
+    }
+
+    @Test
+    public void test6() {
+        s = "Bob    Loves  Alice   ";
+        assertEquals("Alice Loves Bob", solution2.reverseWords(s));
+        assertEquals("Alice Loves Bob", solution3.reverseWords(s));
     }
 }
