| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | --- | 
					
						
							|  |  |  | id: 5900f4c21000cf542c50ffd4 | 
					
						
							| 
									
										
										
										
											2021-11-19 10:31:54 -08:00
										 |  |  | title: 'Problema 340: Função maluca' | 
					
						
							| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | challengeType: 5 | 
					
						
							|  |  |  | forumTopicId: 301999 | 
					
						
							|  |  |  | dashedName: problem-340-crazy-function | 
					
						
							|  |  |  | --- | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | # --description--
 | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
											2021-11-19 10:31:54 -08:00
										 |  |  | Para números inteiros fixos $a$, $b$, $c$, defina a função maluca $F(n)$ da seguinte forma: | 
					
						
							| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2021-11-19 10:31:54 -08:00
										 |  |  | $$\begin{align} & F(n) = n - c \\;\text{ para todo } n > b \\\\ & F(n) = F(a + F(a + F(a + F(a + n)))) \\;\text{ para todo } n ≤ b. \end{align}$$ | 
					
						
							| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2021-11-19 10:31:54 -08:00
										 |  |  | Além disso, defina $S(a, b, c) = \displaystyle\sum_{n = 0}^b F(n)$. | 
					
						
							| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2021-11-19 10:31:54 -08:00
										 |  |  | Por exemplo, se $a = 50$, $b = 2000$ e $c = 40$, então $F(0) = 3240$ e $F(2000) = 2040$. Além disso, $S(50, 2000, 40) = 5.204.240$. | 
					
						
							| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | 
 | 
					
						
							| 
									
										
										
										
											2021-11-19 10:31:54 -08:00
										 |  |  | Encontre os últimos 9 algarismos de $S({21}^7, 7^{21}, {12}^7)$. | 
					
						
							| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | 
 | 
					
						
							|  |  |  | # --hints--
 | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
											2021-11-19 10:31:54 -08:00
										 |  |  | `crazyFunction()` deve retornar `291504964`. | 
					
						
							| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | 
 | 
					
						
							|  |  |  | ```js | 
					
						
							| 
									
										
										
										
											2021-11-19 10:31:54 -08:00
										 |  |  | assert.strictEqual(crazyFunction(), 291504964); | 
					
						
							| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | ``` | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | # --seed--
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | ## --seed-contents--
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | ```js | 
					
						
							| 
									
										
										
										
											2021-11-19 10:31:54 -08:00
										 |  |  | function crazyFunction() { | 
					
						
							| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | 
 | 
					
						
							|  |  |  |   return true; | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | 
 | 
					
						
							| 
									
										
										
										
											2021-11-19 10:31:54 -08:00
										 |  |  | crazyFunction(); | 
					
						
							| 
									
										
										
										
											2021-06-15 00:49:18 -07:00
										 |  |  | ``` | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | # --solutions--
 | 
					
						
							|  |  |  | 
 | 
					
						
							|  |  |  | ```js | 
					
						
							|  |  |  | // solution required | 
					
						
							|  |  |  | ``` |