繁华模拟赛 David与Vincent的博弈游戏

#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn = 100005;
struct edge{
    int to;
    int nxt;
};
int n,g[maxn],dep[maxn],dpd[maxn],dpv[maxn];
int head[maxn],cnt;
edge e[maxn];
inline void add_edge(int u,int v){
    cnt++;
    e[cnt].to = v;
    e[cnt].nxt = head[u];
    head[u] = cnt;
}
void input(){
    cin>>n;
    int u,v;
    for(int i = 1;i < n;i++){
        scanf("%d%d",&u,&v);
        add_edge(u,v);
    }
}
void dfs(bool dep,int x){
    if(!head[x]){
        dpd[x] = dpv[x] = g[x] = 1;
        return;
    }
    for(int i = head[x];i;i = e[i].nxt){
        dfs(!dep,e[i].to);
        g[x] += g[e[i].to];
    }
    dpv[x] = dpd[x] = 1;
    if(dep){
        int sum = 0;
        for(int i = head[x];i;i = e[i].nxt){
            sum += dpv[e[i].to] - 1;
            dpd[x] = max(dpd[x],g[x]-g[e[i].to]+dpd[e[i].to]);
        }
        dpv[x] = max(dpv[x],sum+1);
    }else{
        int sum = 0;
        for(int i = head[x];i;i = e[i].nxt){
            sum += dpd[e[i].to] - 1;
            dpv[x] = max(dpv[x],g[x]-g[e[i].to]+dpv[e[i].to]);
        }
        dpd[x] = max(dpd[x],sum+1);
    }
}
int main(){
    freopen("game.in","r",stdin);
    freopen("game.out","w",stdout);
    input();
    dfs(true,1);
    cout<<dpd[1]<<" "<<g[1] - dpv[1] + 1;
    return 0;
}

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<vector>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<cstdlib>
#include<string>
#include<bitset>
#define INF 1000000000
#define N 200005
#define fi first
#define se second
#define debug(x) cout<<#x<<"="<<x<<endl
#define MP(x,y) make_pair(x,y)
using namespace std;
typedef long long LL;
typedef pair<int,int> pii;
int dp[N],fa[N],lf[N],m;
vector<int> G[N];
void dfs1(int x,int d)
{
    int v,i;
    if(d==1) dp[x]=INF;
    else dp[x]=0;
    for(i=0;i<G[x].size();i++)
    {
        v=G[x][i];
        if(fa[x]!=v)
        {
            lf[x]=1;
            fa[v]=x;
            dfs1(v,d^1);
            if(d==1)
                dp[x]=min(dp[x],dp[v]);
            else dp[x]+=dp[v];
        }
    }
    if(!lf[x])
        dp[x]=1,m++;
}

void dfs2(int x,int d)
{
    int v,i;
    if(d==1) dp[x]=0;
    else dp[x]=INF;
    for(i=0;i<G[x].size();i++)
    {
        v=G[x][i];
        if(fa[x]!=v)
        {
            lf[x]=1;
            fa[v]=x;
            dfs2(v,d^1);
            if(d==1)
                dp[x]+=dp[v];
            else dp[x]=min(dp[x],dp[v]);
        }
    }
    if(!lf[x])
        dp[x]=1;
    //debug(x);
    //debug(dp[x]);
}

int main()
{
    int n,i,a,b;
    freopen("game.in","r",stdin);
    freopen("game.out","w",stdout);
    cin>>n;
    for(i=1;i<n;i++)
    {
        scanf("%d%d",&a,&b);
        G[a].push_back(b);
        //G[b].push_back(a);
    }
    dfs1(1,1);
    cout<<m-dp[1]+1<<' ';
    dfs2(1,1);
    cout<<dp[1]<<endl;
    return 0;
}
// davidlee1999WTK 2015/
// srO myk Orz
//ios::sync_with_stdio(false);