题目描述
Bessie is playing a number game against Farmer John, and she wants you to help her achieve victory.
Game i starts with an integer N_i (1 <= N_i <= 1,000,000). Bessie goes first, and then the two players alternate turns. On each turn, a player can subtract either the largest digit or the smallest non-zero digit from the current number to obtain a new number. For example, from 3014 we may subtract either 1 or 4 to obtain either 3013 or 3010, respectively. The game continues until the number becomes 0, at which point the last player to have taken a turn is the winner.
Bessie and FJ play G (1 <= G <= 100) games. Determine, for each game, whether Bessie or FJ will win, assuming that both play perfectly (that is, on each turn, if the current player has a move that will guarantee his or her win, he or she will take it).
Consider a sample game where N_i = 13. Bessie goes first and takes 3, leaving 10. FJ is forced to take 1, leaving 9. Bessie takes the remainder and wins the game.
贝茜和约翰在玩一个数字游戏.贝茜需要你帮助她.
游戏一共进行了G(1≤G≤100)场.第i场游戏开始于一个正整数Ni(l≤Ni≤1,000,000).游
戏规则是这样的:双方轮流操作,将当前的数字减去一个数,这个数可以是当前数字的最大数码,也可以是最小的非0数码.比如当前的数是3014,操作者可以减去1变成3013,也可以减去4变成3010.若干次操作之后,这个数字会变成0.这时候不能再操作的一方为输家. 贝茜总是先开始操作.如果贝茜和约翰都足够聪明,执行最好的策略.请你计算最后的赢家.
比如,一场游戏开始于13.贝茜将13减去3变成10.约翰只能将10减去1变成9.贝茜再将9减去9变成0.最后贝茜赢.
输入输出格式
输入格式:* Line 1: A single integer: G
* Lines 2..G+1: Line i+1 contains the single integer: N_i
输出格式:* Lines 1..G: Line i contains 'YES' if Bessie can win game i, and 'NO' otherwise.
输入输出样例
说明
For the first game, Bessie simply takes the number 9 and wins. For the second game, Bessie must take 1 (since she cannot take 0), and then FJ can win by taking 9.
考虑用 sg 函数,
那么 sg[ i ]=mex( sg[ i-min ],sg[ i-max ]);
然后 O(1) 询问即可;
#include<iostream> #include<cstdio> #include<algorithm> #include<cstdlib> #include<cstring> #include<string> #include<cmath> #include<map> #include<set> #include<vector> #include<queue> #include<bitset> #include<ctime> #include<deque> #include<stack> #include<functional> #include<sstream> //#include<cctype> //#pragma GCC optimize("O3") using namespace std; #define maxn 1000005 #define inf 0x3f3f3f3f #define INF 9999999999 #define rdint(x) scanf("%d",&x) #define rdllt(x) scanf("%lld",&x) #define rdult(x) scanf("%lu",&x) #define rdlf(x) scanf("%lf",&x) #define rdstr(x) scanf("%s",x) typedef long long ll; typedef unsigned long long ull; typedef unsigned int U; #define ms(x) memset((x),0,sizeof(x)) const long long int mod = 1e9 + 7; #define Mod 1000000000 #define sq(x) (x)*(x) #define eps 1e-3 typedef pair<int, int> pii; #define pi acos(-1.0) //const int N = 1005; #define REP(i,n) for(int i=0;i<(n);i++) typedef pair<int, int> pii; inline ll rd() { ll x = 0; char c = getchar(); bool f = false; while (!isdigit(c)) { if (c == '-') f = true; c = getchar(); } while (isdigit(c)) { x = (x << 1) + (x << 3) + (c ^ 48); c = getchar(); } return f ? -x : x; } ll gcd(ll a, ll b) { return b == 0 ? a : gcd(b, a%b); } ll sqr(ll x) { return x * x; } /*ll ans; ll exgcd(ll a, ll b, ll &x, ll &y) { if (!b) { x = 1; y = 0; return a; } ans = exgcd(b, a%b, x, y); ll t = x; x = y; y = t - a / b * y; return ans; } */ ll qpow(ll a, ll b, ll c) { ll ans = 1; a = a % c; while (b) { if (b % 2)ans = ans * a%c; b /= 2; a = a * a%c; } return ans; } int n; int sg[maxn]; int vis[10]; int mex() { for (int i = 0;; i++) { if (!vis[i])return i; } } void init(int Max) { sg[0] = 0; for (int i = 1; i <= Max; i++) { int tmp = i; ms(vis); int minn = 10, maxx = -1; while (tmp) { if(tmp%10!=0) minn = min(minn, tmp % 10), maxx = max(maxx, tmp % 10); tmp /= 10; } if (maxx != -1)vis[sg[i - maxx]] = 1; if (minn != 10)vis[sg[i - minn]] = 1; sg[i] = mex(); } } int main() { //ios::sync_with_stdio(0); rdint(n); init(maxn); while (n--) { int x; rdint(x); if (sg[x] == 0)cout << "NO" << endl; else cout << "YES" << endl; } return 0; }