Submission #253921

#	Time	Username	Problem	Language	Result	Execution time	Memory
253921		IgorI	Cats or Dogs (JOI18_catdog)	C++17	100 / 100	327 ms	52776 KiB

catdog

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int INF = 1e8;
const int N = 100002;

struct Table{
    int a00, a01, a10, a11;
    Table()
    {
        a00 = a11 = 0;
        a01 = a10 = 1;
    }
};

Table Merge(Table &A, Table &B)
{
    Table S;
    S.a00 = min(A.a00 + B.a00, A.a01 + B.a10);
    S.a01 = min(A.a00 + B.a01, A.a01 + B.a11);
    S.a11 = min(A.a10 + B.a01, A.a11 + B.a11);
    S.a10 = min(A.a10 + B.a00, A.a11 + B.a10);
    return S;
}

struct Sollution{
    int s;
    vector<Table> tree;
    Sollution(int _n)
    {
        for (s = 1; s < _n; s *= 2) ;
        tree.resize(2 * s);
    }
    void Change(int i, int &cost0, int &cost1)
    {
        i += s;
        tree[i].a00 += cost0;
        tree[i].a01 += cost0;
        tree[i].a10 += cost1;
        tree[i].a11 += cost1;
        for (i /= 2; i; i /= 2)
            tree[i] = Merge(tree[2 * i], tree[2 * i + 1]);
    }
    void Cost(int &d0, int &d1)
    {
        int minc0 = min(tree[1].a00, tree[1].a01), minc1 = min(tree[1].a10, tree[1].a11);
        d0 = min(minc0, minc1 + 1);
        d1 = min(minc0 + 1, minc1);
    }
};

ll n;
vector<int> graph[N];
ll x[N];
ll papa[N];
ll sz[N];

int main_child[N];
vector<int> other_child[N];
vector<vector<int> > route;
vector<Sollution> hld;
int route_pos[N];
int route_id[N];

void dfs1(int v, int p)
{
    papa[v] = p;
    sz[v] = 1;
    for (auto u : graph[v]) if (u != p)
    {
        dfs1(u, v);
        sz[v] += sz[u];
    }
}

void dfs2(int v, int p)
{
    int mxsz = 0, id = -1;
    for (auto u : graph[v]) if (u != p)
    {
        if (sz[u] > mxsz)
        {
            mxsz = sz[u];
            id = u;
        }
    }
    main_child[v] = id;
    for (auto u : graph[v]) if (u != p)
    {
        dfs2(u, v);
        if (u != id) other_child[v].push_back(u);
    }
}

int answer()
{
    Table T = hld[0].tree[1];
    return min(min(T.a00, T.a01), min(T.a10, T.a11));
}

void initialize(int n0, vector<int> a, vector<int> b)
{
    n = n0;
    for (int i = 0; i < n - 1; i++)
    {
        a[i]--, b[i]--;
        graph[a[i]].push_back(b[i]);
        graph[b[i]].push_back(a[i]);
    }
    for (int i = 0; i < n; i++)
    {
        x[i] = -1;
    }
    dfs1(0, 0);
    dfs2(0, 0);
    for (int i = 0; i < n; i++)
    {
        route_id[i] = -1;
        route_pos[i] = -1;
    }
    for (int i = 0; i < n; i++)
    {
        if (route_id[i] == -1)
        {
            vector<int> r;
            int x = i;
            while (x != -1)
            {
                r.push_back(x);
                x = main_child[x];
            }
            for (int j = 0; j < r.size(); j++)
            {
                route_id[r[j]] = route.size();
                route_pos[r[j]] = j;
            }
            route.push_back(r);
            hld.push_back(Sollution(r.size()));
        }
    }
}

void Change(int v, int cost0, int cost1)
{
    while (1)
    {
        int x = route_id[v];
        int y = route_pos[v];
        int oldd0, oldd1, d0, d1;
        hld[x].Cost(oldd0, oldd1);
        hld[x].Change(y, cost0, cost1);
        hld[x].Cost(d0, d1);
        v = route[x][0];
        if (v == 0) return;
        v = papa[v], cost0 = d0 - oldd0, cost1 = d1 - oldd1;
    }
}

int cat(int v)
{
    v--;
    x[v] = 0;
    Change(v, 0, INF);
    return answer();
}

int dog(int v)
{
    v--;
    x[v] = 1;
    Change(v, INF, 0);
    return answer();
}

int neighbor(int v)
{
    v--;
    if (x[v] == 0) Change(v, 0, -INF);
    if (x[v] == 1) Change(v, -INF, 0);
    x[v] = -1;
    return answer();
}

Compilation message (stderr)

catdog.cpp: In function 'void initialize(int, std::vector<int>, std::vector<int>)':
catdog.cpp:135:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (int j = 0; j < r.size(); j++)
                             ~~^~~~~~~~~~

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