N个人围成一圈报数,报到某一个数m的就出局,问你最后剩下来的人的号码?
网上通用约瑟夫环的算法是:
//函数接收n和m,返回最后出圈的是第几个人
/*e.g. yuesefu(5,2)=3
yuesefu(2,100)=1*/
int yuesefu(int n,int m)
{
int i,r=0;
for (i=2;i <=n;i++) r=(r+m)%i;
return r+1;
}
用python实现上面算法为:
def yuesefu2(n, m):
# 网上常见方法,答案准确
# yuesefu2(50, 5)=19
i = 0
r = 0
for i in range(2, n + 1):
r = (r + m) % i
return r + 1
用python模拟报数出局的方法为:
def yuesefu3(n, m):
a = range(1, n + 1)
b = []
i = 0 # 指针
while n > 1:
i = i + m
if i > n:
i = i % n
b.append(a.pop(i - 1))
# print a.pop(i-1)
n = n - 1
i = i - 1
if i == n or i == -1: # 特别处理,如果正好弹出最后一个,i值归0
i = 0
b.append(a[0])
return b
if __name__ == ‘__main__‘:
n = 60
m = 99
print u‘约瑟环2:‘ + str(yuesefu2(n, m))
print u‘约瑟环3:‘ + str(yuesefu3(n, m))
50人报5出局答案为:
约瑟环2:19
约瑟环3:[5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 6, 12, 18, 24, 31, 37, 43, 49, 7, 14, 22, 29, 38, 46, 3, 13, 23, 33, 42, 2, 16, 27, 39, 1, 17, 32, 47, 11, 34, 4, 26, 48, 28, 9, 44, 41, 8, 21, 36, 19]
30人报3出局答案为:
约瑟环2:29
约瑟环3:[3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 4, 8, 13, 17, 22, 26, 1, 7, 14, 20, 28, 5, 16, 25, 10, 23, 11, 2, 19, 29]
60人报99出局答案为:
约瑟环2:55
约瑟环3:[39, 19, 1, 45, 30, 17, 7, 58, 52, 48, 46, 47, 51, 57, 6, 16, 29, 44, 10, 32, 2, 31, 9, 43, 28, 21, 14, 13, 20, 27, 42, 8, 38, 22, 4, 60, 11, 26, 54, 36, 34, 41, 12, 56, 5, 40, 49, 23, 33, 25, 18, 15, 37, 50, 59, 53, 24, 3, 35, 55]