第一章作业

Author: ruyiluo

Diff for: Homework/ryl/lz_episode_01/fibonacci.py

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+# 输出小于100的斐波那契数列
+# 代码学习： 这里的b相当于是当前位置的数，而a每次都保存了前一次的值
+print('小于100的斐波那契数列')
+a = 0
+b = 1
+while b < 100:
+    print(b, end = " ")
+    a, b = b, a + b
+    

Diff for: Homework/ryl/lz_episode_01/geometrically.py

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+# 求整数的几何级数
+# 等比数列求和公式： Sn = a(1-q**n)/(1-q)
+
+print('几何级数')
+a = int(input('a:'))
+q = int(input('q:'))
+n = int(input('n:'))
+
+sum = a*(1-q**n)/(1-q)
+
+print(sum)

Diff for: Homework/ryl/lz_episode_01/prime_number.py

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+# 暴力求解：质数只有1和本身是自己的因数，所以从2到本身减一去全部试探一遍
+# 搜索到i**0.5就可以了
+
+import time
+import math
+print('100万以内的质数')
+start = time.time()
+num = int(input('number:'))
+ret = []
+l = [2, 3, 5, 7, 9]
+for i in range(2, num+1):
+    for a in l:
+        if i%a == 0:
+            continue
+            
+    for j in range(2, int(i**0.5)):
+        if i%j == 0:
+            break
+    else:
+        ret.append(i)
+
+print('Counts：', len(ret))
+print('Time:', time.time()-start)