#70 爬楼梯

Author: Isaaclot

main/src/array/LC_70_ClimbingStairs.java

@@ -72,4 +72,19 @@ public int climbStairs_twice_70(int n) {
         }
         return dp;
     }
+
+    /**
+     * 爬楼梯
+     */
+    public int climbStairs_4Week(int n) {
+        if (n == 1) return 1;
+        if (n == 2) return 2;
+        int p1 = 1, p2 = 2, p3 = p1 + p2;
+        for (int i = 3; i <= n; i++) {
+            p3 = p1 + p2;
+            p1 = p2;
+            p2 = p3;
+        }
+        return p3;
+    }
 }

main/test/array/LC_70_ClimbingStairsTest.java

@@ -29,4 +29,10 @@ public void climbStairs_twice_70() {
         assertEquals(5, climbingStairs.climbStairs_twice_70(4));
         assertEquals(3, climbingStairs.climbStairs_twice_70(3));
     }
+
+    @Test
+    public void climbStairs_twice_4Week() {
+        assertEquals(5, climbingStairs.climbStairs_4Week(4));
+        assertEquals(3, climbingStairs.climbStairs_4Week(3));
+    }
 }