UVA 847 - A Multiplication Game(博弈)

UVA 847 - A Multiplication Game

题目链接

题意：一个数一开始是1，每次轮流乘2-9，谁先大于n谁就赢，问谁胜

思路：博弈，找出必胜态，2-9为stan，10-18为ollie,19-162为stan...发现都是乘2乘9交替

代码：

#include <stdio.h>#include <string.h>#include <math.h>long long n;bool judge(long long n) {long long a = 1, b = 1;int flag = 1;while (1) {if (flag) {a = b + 1;b *= 9;if (a <= n && n <= b) return true;  flag = 0;    }  else {  a = b + 1;  b *= 2;  if (a <= n && n <= b) return false;  flag = 1;  } }}int main() {while (~scanf("%lld", &n)) {printf("%s wins.\n", judge(n)?"Stan":"Ollie"); }return 0;}