add 647

fishercoder1534 · fishercoder1534 · commit 51f67fc77bf4 · 2021-03-27T09:07:56.000-07:00
diff --git a/src/main/java/com/fishercoder/solutions/_647.java b/src/main/java/com/fishercoder/solutions/_647.java
@@ -25,4 +25,32 @@ private int extendPalindrome(String s, int left, int right) {
             return count;
         }
     }
+
+    public static class Solution2 {
+        /**
+         * Simple brute force solution is accepted as well, although not ideal in terms of time complexity: O(n^2)
+         */
+        public int countSubstrings(String s) {
+            int result = 0;
+            for (int i = 0; i < s.length(); i++) {
+                for (int j = i + 1; j <= s.length(); j++) {
+                    if (isPal(s.substring(i, j))) {
+                        result++;
+                    }
+                }
+            }
+            return result;
+        }
+
+        private boolean isPal(String str) {
+            int i = 0;
+            int j = str.length() - 1;
+            while (i < j) {
+                if (str.charAt(i++) != str.charAt(j--)) {
+                    return false;
+                }
+            }
+            return true;
+        }
+    }
 }
diff --git a/src/test/java/com/fishercoder/_647Test.java b/src/test/java/com/fishercoder/_647Test.java
@@ -8,15 +8,18 @@
 
 public class _647Test {
     private static _647.Solution1 solution1;
+    private static _647.Solution2 solution2;
 
     @BeforeClass
     public static void setup() {
         solution1 = new _647.Solution1();
+        solution2 = new _647.Solution2();
     }
 
     @Test
     public void test1() {
         assertEquals(3, solution1.countSubstrings("abc"));
+        assertEquals(3, solution2.countSubstrings("abc"));
     }
 
 }

Original file line number	Diff line number	Diff line change
`@@ -8,15 +8,18 @@`
`8`	`8`
`9`	`9`	`public class _647Test {`
`10`	`10`	`private static _647.Solution1 solution1;`
	`11`	`+ private static _647.Solution2 solution2;`
`11`	`12`
`12`	`13`	`@BeforeClass`
`13`	`14`	`public static void setup() {`
`14`	`15`	`solution1 = new _647.Solution1();`
	`16`	`+ solution2 = new _647.Solution2();`
`15`	`17`	`}`
`16`	`18`
`17`	`19`	`@Test`
`18`	`20`	`public void test1() {`
`19`	`21`	`assertEquals(3, solution1.countSubstrings("abc"));`
	`22`	`+ assertEquals(3, solution2.countSubstrings("abc"));`
`20`	`23`	`}`
`21`	`24`
`22`	`25`	`}`