issue #42 피보나치 함수

sowon-dev · sowon-dev · commit 398e9224330a · 2021-06-29T07:28:54.000+09:00
diff --git a/src/backjoon/_1003.java b/src/backjoon/_1003.java
@@ -0,0 +1,71 @@
+package backjoon;
+// https://www.acmicpc.net/problem/1003
+// 피보나치 함수
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+public class _1003 {
+  public static int cntZero = 0;
+  public static int cntOne = 0;
+  static int zero_plus_one;
+
+  public static void main(String[] args) throws IOException {
+    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+    int T = Integer.parseInt(br.readLine());
+    StringBuilder sb = new StringBuilder();
+
+    for(int i=0; i<T; i++){
+      int n = Integer.parseInt(br.readLine());
+      fibonacci(n);
+      sb.append(cntZero).append(' ').append(cntOne).append("\n");
+//      cntZero = 0;
+//      cntOne = 0;
+    }
+    System.out.println(sb);
+  }
+
+  // sol1 시간초과
+  /*
+  static int fibonacci(int n){
+    if(n == 0){
+      cntZero++;
+      return 0;
+    } else if (n == 1){
+      cntOne++;
+      return 1;
+    } else {
+      return fibonacci(n-1) + fibonacci(n-2);
+    }
+  }
+  */
+
+  // so2 memory 11432 runtime 76
+  // 규칙을 찾아서 풀기
+  static void fibonacci(int N) {
+    // 반드시 초기화 해야한다.
+    cntZero = 1;
+    cntOne = 0;
+    zero_plus_one = 1;
+
+    for (int i = 0; i < N; i++) {
+      cntZero = cntOne;
+      cntOne = zero_plus_one;
+      zero_plus_one = cntZero + cntOne;
+    }
+
+  }
+}
+/*
+input
+3
+0
+1
+3
+
+output
+1 0
+0 1
+1 2
+ */
