Submission #500860

#	Time	Username	Problem	Language	Result	Execution time	Memory
500860		balbit	Cats or Dogs (JOI18_catdog)	C++14	100 / 100	257 ms	37284 KiB

catdog

#include "catdog.h"

#include <bits/stdc++.h>
#define int ll
using namespace std;
#define ll long long
#define y1 zck_is_king
#define pii pair<ll, ll>
#define ull unsigned ll
#define f first
#define s second
#define ALL(x) x.begin(),x.end()
#define SZ(x) (int)x.size()
#define SQ(x) (x)*(x)
#define MN(a,b) a = min(a,(__typeof__(a))(b))
#define MX(a,b) a = max(a,(__typeof__(a))(b))
#define pb push_back
#define REP(i,n) for (int i = 0; i<n; ++i)
#define RREP(i,n) for (int i = n-1; i>=0; --i)
#define REP1(i,n) for (int i = 1; i<=n; ++i)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#ifdef BALBIT
#define IOS()
#define bug(...) fprintf(stderr,"#%d (%s) = ",__LINE__,#__VA_ARGS__),_do(__VA_ARGS__);
template<typename T> void _do(T &&x){cerr<<x<<endl<<flush;}
template<typename T, typename ...S> void _do(T &&x, S &&...y){cerr<<x<<", ";_do(y...);}
#else
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0);
#define endl '\n'
#define bug(...)
#endif

const int iinf = 1e9+10;
const ll inf = 1ll<<29;
const ll mod = 1e9+7 ;


void GG(){cout<<"0\n"; exit(0);}

ll mpow(ll a, ll n, ll mo = mod){ // a^n % mod
    ll re=1;
    while (n>0){
        if (n&1) re = re*a %mo;
        a = a*a %mo;
        n>>=1;
    }
    return re;
}

ll inv (ll b, ll mo = mod){
    if (b==1) return b;
    return (mo-mo/b) * inv(mo%b,mo) % mo;
}

const int maxn = 1e5+5;

struct segtree{
    // segtree for this chain
    int MAXN;
    vector<array<array<int,2>, 2> > s; // s[o][a][b]: from type a (higher) to type b (lower) 0 is cat, 1 is dog

    void MO(int p, int n0, int n1, int o, int l, int r) {
        if (l > p || r < p) return;
        if (l == r) {
            s[o][0][0]=n0;
            s[o][1][1]=n1;
            s[o][0][1]=inf;
            s[o][1][0]=inf;
            return;
        }
        int mid = (l+r)/2;
        MO(p,n0,n1,o*2,l,mid);
        MO(p,n0,n1,o*2+1,mid+1,r);

        REP(i,2) REP(j,2) {
            s[o][i][j] = inf;
            REP(a,2) REP(b,2){
                MN(s[o][i][j], s[o*2][i][a] + s[o*2+1][b][j] + (a!=b));
            }
        }
    }

    void MO(int p, int n0, int n1) {
        MO(p,n0,n1,1,0,MAXN-1);
    }

    array<int, 2> get(){
        array<int, 2> re = {{inf, inf}};
        REP(t,2) REP(i,2) REP(j,2) {
            MN(re[t], s[1][i][j] + (i!=t));
        }
        return re;
    }

    int gans(){
        int re = inf;
        REP(i,2) REP(j,2) {
//            bug(i,j,s[1][i][j]);
            MN(re, s[1][i][j]);
        }
        return re;
    }

    segtree(){}

    void init(int ss){
        MAXN = ss;
        s.resize(ss*4, {{{{inf,inf}}, {{inf, inf}}}});
    }
};

//int treeidx[maxn]; // position on chain, with 0 being the head
int head[maxn]; // head of each node
int sz[maxn], par[maxn];
vector<int> g[maxn];
int catdog[maxn], dep[maxn]; // -1:nothing, 0:cat, 1:dog
int ifcat[maxn], ifdog[maxn]; // cost of being cat or dog

void dfs(int v, int p) {
    sz[v] = 1;
    for (int u : g[v]) {
        if (u != p) {
            par[u] = v;
            dep[u] = dep[v] + 1;
            dfs(u,v);
            sz[v] += sz[u];
        }
    }
}

int chainsize[maxn];

void dfs2(int v, int p) {
    chainsize[head[v]]++;
    int mx = 0, mxc = -1;
    for (int u : g[v]) {
        if (u!=p) {
            if (sz[u] > mx) {
                mx = sz[u]; mxc = u;
            }
        }
    }
    for (int u : g[v]) {
        if (u !=p) {
            if (u == mxc) {
                head[u] = head[v];
            }else{
                head[u] = u;
            }
            dfs2(u,v);
        }
    }
}

segtree TT[maxn]; // for each head

void upd(int v) {
    // update a node
    if (catdog[v] == -1) {
        // no animal
        TT[head[v]].MO(dep[v] - dep[head[v]], ifcat[v], ifdog[v]);
    }else if (catdog[v] == 0) {
        bug("hello/");
        TT[head[v]].MO(dep[v] - dep[head[v]], ifcat[v], inf);
        // cat
    }else{
        // doge
        bug("hello/ dog");
        TT[head[v]].MO(dep[v] - dep[head[v]], inf, ifdog[v]);
    }
}

void chainupd(int v) {
    while (1) {
        array<int, 2> old = TT[head[v]].get();
        upd(v);
        if (head[v] == 0) break;
        array<int, 2> yo = TT[head[v]].get();
        int nxt = par[head[v]];
        ifcat[nxt] += yo[0] - old[0];
        ifdog[nxt] += yo[1] - old[1];
        v = nxt;
    }
}

void initialize(signed n, vector<signed> a, vector<signed> b) {
    REP(i,n-1) {
        g[a[i]-1].pb(b[i]-1);
        g[b[i]-1].pb(a[i]-1);
    }
    dfs(0, -1);
    dfs2(0,-1);
    REP(i,n) {
        bug(i, head[i], chainsize[head[i]]);
        if (head[i] == i) {
            TT[i].init(chainsize[i]);
        }
    }
    REP(i,n) catdog[i] = -1;
    REP(i,n) {
        upd(i);
    }


}

signed yar(signed v, signed nw) {
    --v;
    catdog[v] = nw;
    chainupd(v);
//    array<int, 2> ho = TT[0].get();
    int ret = TT[0].gans();
    bug(ret);
    return ret;
}

signed cat(signed v) {
    return yar(v,0);
}

signed dog(signed v) {
    return yar(v,1);
}

signed neighbor(signed v) {
    return yar(v,-1);
}

/*
5
1 2
2 3
2 4
1 5
7

*/

• Subtask 1: 8 / 8
• Subtask 2: 30 / 30
• Subtask 3: 62 / 62