圆圈中最后剩下的数字

JushuangQiao · JushuangQiao · commit 16917882c94a · 2017-11-10T13:48:23.000+08:00
diff --git a/sixth/fourth/fourty_five.py b/sixth/fourth/fourty_five.py
@@ -0,0 +1,17 @@
+# coding=utf-8
+"""
+0到n-1排成一圈，从0开始每次数m个数删除，求最后剩余的数
+当 n > 1 时： f(n,m) = [f(n-1, m)+m]%n,当 n = 1 时： f(n,m)=0
+"""
+
+
+def last_num(n, m):
+    ret = 0
+    if n == 1:
+        return 0
+    for i in range(2, n+1):
+        ret = (m + ret) % i
+    return ret
+
+if __name__ == '__main__':
+    print last_num(3, 4)
