add a solution for 118

fishercoder1534 · fishercoder1534 · commit 23e0ca96ab13 · 2021-09-15T15:48:43.000-07:00
diff --git a/src/main/java/com/fishercoder/solutions/_118.java b/src/main/java/com/fishercoder/solutions/_118.java
@@ -1,6 +1,7 @@
 package com.fishercoder.solutions;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 public class _118 {
@@ -41,4 +42,28 @@ public List<List<Integer>> generate(int numRows) {
             return result;
         }
     }
+
+    public static class Solution3 {
+        /**
+         * my completely original solution on 9/15/2021
+         */
+        public List<List<Integer>> generate(int numRows) {
+            List<List<Integer>> ans = new ArrayList<>();
+            for (int i = 0; i < numRows; i++) {
+                if (ans.isEmpty()) {
+                    ans.add(Arrays.asList(1));
+                } else {
+                    List<Integer> prev = ans.get(ans.size() - 1);
+                    List<Integer> curr = new ArrayList<>(prev.size() + 1);
+                    curr.add(1);
+                    for (int j = 0; j < prev.size() - 1; j++) {
+                        curr.add(prev.get(j) + prev.get(j + 1));
+                    }
+                    curr.add(1);
+                    ans.add(curr);
+                }
+            }
+            return ans;
+        }
+    }
 }
diff --git a/src/test/java/com/fishercoder/_118Test.java b/src/test/java/com/fishercoder/_118Test.java
@@ -8,11 +8,13 @@
 public class _118Test {
     private static _118.Solution1 solution1;
     private static _118.Solution2 solution2;
+    private static _118.Solution3 solution3;
 
     @BeforeClass
     public static void setup() {
         solution1 = new _118.Solution1();
         solution2 = new _118.Solution2();
+        solution3 = new _118.Solution3();
     }
 
     @Test
@@ -25,4 +27,9 @@ public void test2() {
         CommonUtils.printListList(solution2.generate(5));
     }
 
+    @Test
+    public void test3() {
+        CommonUtils.printListList(solution3.generate(5));
+    }
+
 }
