博弈论练习2
博弈論練習2
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1.AGC010F - Tree Game
題目描述
Solution
一道簡單博弈題(不知道為啥能作為AGC的F題)。
考慮樹形dpdpdp,設f[x]f[x]f[x]表示以xxx為根的子樹中是否先手必勝。
則f[x]=1f[x]=1f[x]=1當且僅當能找到xxx的子節點vvv滿足f[v]=0f[v]=0f[v]=0且a[x]>a[v]a[x]>a[v]a[x]>a[v](因為這樣就可以把后手摁死在vvv子樹里,讓后手輸掉,自己就贏了)。
對于每一個結點都把它當做整一棵樹的根dpdpdp一遍即可。
時間復雜度O(n2)O(n^2)O(n2)
2.SPOJ COT3 - Combat on a tree
題目描述
Solution
一道SG (數據結構)好題。
每一次選擇一條到根的路徑清零就相當于斷成若干個獨立的子樹,因此就可以求子樹SGSGSG值計算答案,用可持久化trietrietrie樹維護整體xorxorxor和求mexmexmex。
#include <vector> #include <list> #include <map> #include <set> #include <deque> #include <queue> #include <stack> #include <bitset> #include <algorithm> #include <functional> #include <numeric> #include <utility> #include <sstream> #include <iostream> #include <iomanip> #include <cstdio> #include <cmath> #include <cstdlib> #include <cctype> #include <string> #include <cstring> #include <ctime> #include <cassert> #include <string.h> //#include <unordered_set> //#include <unordered_map> //#include <bits/stdc++.h>#define MP(A,B) make_pair(A,B) #define PB(A) push_back(A) #define SIZE(A) ((int)A.size()) #define LEN(A) ((int)A.length()) #define FOR(i,a,b) for(int i=(a);i<(b);++i) #define fi first #define se secondusing namespace std;template<typename T>inline bool upmin(T &x,T y) { return y<x?x=y,1:0; } template<typename T>inline bool upmax(T &x,T y) { return x<y?x=y,1:0; }typedef long long ll; typedef unsigned long long ull; typedef long double lod; typedef pair<int,int> PR; typedef vector<int> VI;const lod eps=1e-11; const lod pi=acos(-1); const int oo=1<<30; const ll loo=1ll<<62; const int mods=998244353; const int MAXN=200005; const int MAXM=MAXN<<5; const int INF=0x3f3f3f3f;//1061109567 /*--------------------------------------------------------------------*/ inline int read() {int f=1,x=0; char c=getchar();while (c<'0'||c>'9') { if (c=='-') f=-1; c=getchar(); }while (c>='0'&&c<='9') { x=(x<<3)+(x<<1)+(c^48); c=getchar(); }return x*f; } int sum[MAXN],c[MAXN],rt[MAXN],sg[MAXN],up[MAXN]; vector<int> e[MAXN],Ans; struct Trie_Tree {int nodenum=0,flag[MAXM],tag[MAXM],dep[MAXM],ch[MAXM][2];void up(int x) { flag[x]=flag[ch[x][0]]&&flag[ch[x][1]]; }void Xor(int x,int y) {if (!x) return;tag[x]^=y; if (y&(1<<(31-dep[x]-1))) swap(ch[x][0],ch[x][1]);}void down(int x){if (!x||!tag[x]) return;Xor(ch[x][0],tag[x]);Xor(ch[x][1],tag[x]);tag[x]=0;}void Insert(int &x,int y,int Dep) { if (!x) dep[x=++nodenum]=Dep;down(x);if (Dep==31) { flag[x]=1; return; } if (y&(1<<(31-dep[x]-1))) Insert(ch[x][1],y,Dep+1);else Insert(ch[x][0],y,Dep+1);up(x);}int Mex(int x){if (!x||dep[x]==31) return 0;if (flag[ch[x][0]]) return (1<<(31-dep[x]-1))+Mex(ch[x][1]);return Mex(ch[x][0]);}int Merge(int x,int y){if (!x||!y) return x+y;if (dep[x]==31) { flag[x]=flag[x]||flag[y]; return x; }down(x),down(y);ch[x][0]=Merge(ch[x][0],ch[y][0]);ch[x][1]=Merge(ch[x][1],ch[y][1]);up(x);return x;} } Trie; void tree_dp(int x,int father) {for (auto v:e[x]){if (v==father) continue;tree_dp(v,x);sum[x]^=sg[v];}if (!c[x]) Trie.Insert(rt[x],sum[x],1);for (auto v:e[x]){if (v==father) continue;Trie.Xor(rt[v],sum[x]^sg[v]);rt[x]=Trie.Merge(rt[x],rt[v]);}sg[x]=Trie.Mex(rt[x]); } void getans(int x,int father) {if (father) up[x]=up[father]^sum[father]^sg[x]; // cout<<x<<" "<<father<<" "<<sum[x]<<" "<<sg[x]<<" "<<up[x]<<endl;for (auto v:e[x]){if (v==father) continue;getans(v,x);}if ((!c[x])&&((up[x]^sum[x])==0)) Ans.PB(x); } int main() {int n=read();for (int i=1;i<=n;i++) c[i]=read();for (int i=1;i<n;i++){int u=read(),v=read();e[u].PB(v);e[v].PB(u);} tree_dp(1,0);getans(1,0);if (!Ans.size()) { puts("-1"); return 0; }sort(Ans.begin(),Ans.end());for (auto v:Ans) printf("%d\n",v);return 0; }3.CF494E.Sharti
題目描述
Solution
典型的翻硬幣博弈模型。
整體的SGSGSG值為所有單獨一個格子為黑色的SGSGSG值的異或和。
離散化行,線段樹維護列信息求解。
4.[ZROJ十連測 Day5].銀
題目描述
Solution
有題解,思路神仙學不來,貼個程序溜了。
#include <vector> #include <list> #include <map> #include <set> #include <deque> #include <queue> #include <stack> #include <bitset> #include <algorithm> #include <functional> #include <numeric> #include <utility> #include <sstream> #include <iostream> #include <iomanip> #include <cstdio> #include <cmath> #include <cstdlib> #include <cctype> #include <string> #include <cstring> #include <ctime> #include <cassert> #include <string.h> //#include <unordered_set> //#include <unordered_map> //#include <bits/stdc++.h>#define MP(A,B) make_pair(A,B) #define PB(A) push_back(A) #define SIZE(A) ((int)A.size()) #define LEN(A) ((int)A.length()) #define FOR(i,a,b) for(int i=(a);i<(b);++i) #define fi first #define se secondusing namespace std;template<typename T>inline bool upmin(T &x,T y) { return y<x?x=y,1:0; } template<typename T>inline bool upmax(T &x,T y) { return x<y?x=y,1:0; }typedef long long ll; typedef unsigned long long ull; typedef long double lod; typedef pair<int,int> PR; typedef vector<int> VI;const lod eps=1e-11; const lod pi=acos(-1); const int oo=1<<30; const ll loo=1ll<<62; const int mods=998244353; const int MAXN=600005; const int INF=0x3f3f3f3f;//1061109567 /*--------------------------------------------------------------------*/ inline int read() {int f=1,x=0; char c=getchar();while (c<'0'||c>'9') { if (c=='-') f=-1; c=getchar(); }while (c>='0'&&c<='9') { x=(x<<3)+(x<<1)+(c^48); c=getchar(); }return x*f; } char st[MAXN]; int cnt[30]; int lowbit(int x){ return x&(-x); } int main() {int n=read(),SG=0;scanf("%s",st+1);reverse(st+1,st+n+1);for (int i=1;i<=n;i++)if (st[i]=='1'){SG^=lowbit(i);for (int j=20;j>=0;j--) cnt[j]+=((i>>j)&1);}int Case=read();while (Case--){int x=n-read()+1,c;if (st[x]=='1') st[x]='0',c=-1;else st[x]='1',c=1;SG^=lowbit(x);for (int j=20;j>=0;j--) cnt[j]+=((x>>j)&1)*c;if (!SG) { puts("0"); continue; }int mx=20;while (!(SG>>mx)) mx--;printf("%d\n",cnt[mx]);}return 0; }5.CF1033GChip Game
題目描述
Solution
8會8會,留坑定補flagflagflag。
總結
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