UVA 1482 - Playing With Stones 题目链接 题意:给定n堆石头,每次选一堆取至少一个.不超过一半的石子,最后不能取的输,问是否先手必胜 思路:数值非常大.无法直接递推sg函数.打出前30项的sg函数找规律 代码: #include <stdio.h> #include <string.h> int t, n; long long num; long long SG(long long x) { return x % 2 == 0 ? x : SG(x /…

题意:nim游戏.加上限制每次不得取走超过当前堆一半的石子 1 ≤ N ≤ 100,1 ≤ ai ≤ 2 ∗ 1018 分析:由于ai过大.所以我们采用SG函数递推找规律. (详见代码) #include<cstdio> using namespace std; typedef long long ll; int T,n;ll x,S; ll GetSG(ll x){ ?GetSG(x>>):x>>; } int main(){ for(scanf("%d&q…

题目链接:https://vjudge.net/problem/UVA-1482 题意: 有n堆石子, 每堆石子有ai(ai<=1e18).两个人轮流取石子,要求每次只能从一堆石子中抽取不多于一半的石子,最后不能取的为输家. 题解: 典型的SG博弈,由于ai的范围很大,所以不能直接求SG值,那么就打表SG值找规律,如下: 发现,当x为偶数时, SG[x] = x/2; 当x为奇数时, SG[x] = SG[x/2],即如下: 代码如下: #include <iostream> #incl…

题意:有n堆石子,分别有a[i]个.两个游戏者轮流操作,每次可以选一堆,拿走至少一个石子,但不能拿走超过一半的石子. 谁不能拿石子就算输,问先手胜负情况 n<=100,1<=a[i]<=2e18 思路:打表找SG函数的规律 当n为偶数时,SG(n)=n/2 当n为奇数时,SG(n)=SG(n/2) #include<cstdio> #include<cstring> #include<iostream> #include<algorithm>…

题意: 有n堆石子,两个人轮流取,每次只能取一堆的至少一个至多一半石子,直到不能取为止. 判断先手是否必胜. 分析: 本题的关键就是求SG函数,可是直接分析又不太好分析,于是乎找规律. 经过一番“巧妙”的分析,有这样一个规律: 如果n是偶数,SG(n) = n / 2; 如果n是奇数,SG(n) = SG(n / 2); 这道题的意义不在于规律是什么,而是要自己能够写出求SG函数值的代码.顺便再体会一下mex(S)的含义. #include <cstring> ; int SG[maxn],…

题意:有N堆石子,每次可以取一堆的不超过半数的石子,没有可取的为输. 思路:假设只有一堆,手推出来,数量x可以表示为2^p-1形式的必输. 但是没什么用,因为最后要的不是0和1,而是SG函数:所以必输的为0,那么其他的呢? 我们可以发现SG=0的位置是1,3,7,15,31.... SG=1,            2,5,11,23.... 可以推出来,也可以打表. (水题,这题可以放这里以后讲课用. sg[]=; ;i<=;i++){ memset(vis,,sizeof(vis)); ;j…

C - Playing With Stones Time Limit:3000MS     Memory Limit:0KB     64bit IO Format:%lld & %llu Submit Status Practice UVALive 5059 Description You and your friend are playing a game in which you and your friend take turns removing stones from piles.…

F - Again Stone Game Time Limit:2000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Description Alice and Bob are playing a stone game. Initially there are n piles of stones and each pile contains some stone. Alice stars the…

S-Nim Time Limit: 1000MS   Memory Limit: 32768KB   64bit IO Format: %I64d & %I64u Submit Status Description Arthur and his sister Caroll have been playing a game called Nim for some time now. Nim is played as follows: The starting position has a numb…

S-Nim Time Limit: 5000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 7262    Accepted Submission(s): 3074 Problem Description Arthur and his sister Caroll have been playing a game called Nim for some time now.…