제출 #891760

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
891760		abysmal	Cat Exercise (JOI23_ho_t4)	C++14	100 / 100	755 ms	68460 KiB

Main

#include<iostream>
#include<stdio.h>
#include<stdint.h>
#include<vector>
#include<algorithm>
#include<utility>
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<iomanip>
#include<string>
#include<math.h>
#include<assert.h>

using namespace std;

const double PI = (double) atan(1.0) * 4;
const int64_t INF = (int64_t) 1e18 + 777;
const int64_t mINF = (int64_t) 2e9 + 777;
const int64_t offset = (int64_t) 1e6 + 777;
const int64_t MOD = 1e9 + 7;
const int nbit = 11;
const int ndig = 10;
const int nchar = 26;
const int p1 = 31;
const int p2 = 53;
const int D = 4;
int dr[D] = {0, 1, 0, -1};
int dc[D] = {1, 0, -1, 0};
// 0 right // 1 down // 2 left // 3 up

int modadd(int t1, int t2)
{
    int res = t1 + t2;
    if(res >= MOD) res -= MOD;

    return res;
}

int modmul(int t1, int t2)
{
    int64_t res = 1LL * t1 * t2;
    return (res % MOD);
}

struct LCA
{
    int n; int t;
    int LOG;
    vector<int> f;
    vector<int> pos;
    vector<int> depth;
    vector<vector<int> > rmq;
    vector<vector<int> > adj;

    LCA(int n_)
    {
        n = n_; t = 0;
        LOG = 0;
        f.resize(n, -1);
        adj.resize(n);
        depth.resize(n, 0);
    }

    void prep()
    {
        DFS();
        while((1 << LOG) <= t) LOG++;
        rmq.resize(LOG, vector<int>(t, 0));
        for(int i = 0; i < t; i++)
        {
            rmq[0][i] = pos[i];
        }

        for(int i = 1; i < LOG; i++)
        {
            for(int j = 0; j + (1 << i) - 1 < t; j++)
            {
                int d1 = depth[ rmq[i - 1][j] ];
                int d2 = depth[ rmq[i - 1][j + (1 << (i - 1))] ];
                if(d1 < d2) rmq[i][j] = rmq[i - 1][j];
                else rmq[i][j] = rmq[i - 1][j + (1 << (i - 1))];
            }
        }
    }

    int getLCA(int i, int j)
    {
        i = f[i]; j = f[j];
        if(i > j) swap(i, j);
        int len = j - i + 1;
        int bt = 31 - __builtin_clz(len);
        if(depth[ rmq[bt][i] ] < depth[ rmq[bt][j - (1 << bt) + 1] ]) return rmq[bt][i];
        return rmq[bt][j - (1 << bt) + 1];
    }

    int dis(int u, int v)
    {
        int x = getLCA(u, v);
        return depth[u] + depth[v] - 2 * depth[x];
    }

    void addEdge(int u, int v)
    {
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    void DFS(int u = 0, int p = -1)
    {
        f[u] = t++;
        pos.push_back(u);

        for(int i = 0; i < (int) adj[u].size(); i++)
        {
            int v = adj[u][i];
            if(v == p) continue;

            depth[v] = depth[u] + 1;
            DFS(v, u);

            pos.push_back(u);
            t++;
        }
    }
};

struct Solution
{
    int n;
    vector<int> a;
    vector<int> ver;
    vector<int> link;
    vector<int> size;
    vector<vector<int> > adj;
    Solution() {}

    void solve()
    {
        cin >> n;
        a.resize(n);
        ver.resize(n, -1);
        LCA lca(n);
        adj.resize(n);
        for(int i = 0; i < n; i++)
        {
            cin >> a[i];
            a[i]--;

            ver[a[i]] = i;
        }

        for(int i = 0; i < n - 1; i++)
        {
            int u; int v;
            cin >> u >> v;
            u--; v--;

            lca.addEdge(u, v);
            adj[u].push_back(v);
            adj[v].push_back(u);
        }
        lca.prep();
        link.resize(n);
        for(int i = 0; i < n; i++)
        {
            link[i] = i;
        }

        vector<int64_t> dp(n, 0);
        for(int i = 0; i < n; i++)
        {
            int u = ver[i];
            for(int j = 0; j < (int) adj[u].size(); j++)
            {
                int v = adj[u][j];
                if(a[v] > a[u]) continue;

                int x = find(v);
                dp[u] = max(dp[u], dp[x] + lca.dis(u, x));
                unite(u, x);
            }
        }

        cout << dp[ver[n - 1]] << "\n";
    }

    int find(int x)
    {
        while(x != link[x])
        {
            x = link[x];
        }
//        cerr << "c = " << c << "\n";
        return x;
    }

    void unite(int x, int y)
    {
        y = find(y);
        link[y] = x;
    }

    int modsub(int t1, int t2)
    {
        int res = t1 - t2;
        if(res < 0) res += MOD;

        return res;
    }

    bool BIT(int& mask, int& j)
    {
        return (mask & MASK(j));
    }

    int64_t Abs(int64_t t1)
    {
        if(t1 < 0) return -t1;
        return t1;
    }

    int MASK(int j)
    {
        return (1 << j);
    }
};

void __startup()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);

//    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);
}

int main()
{
    __startup();
    int t = 1;
//    cin >> t;

    for(int i = 1; i <= t; i++)
    {
        Solution().solve();
    }

    return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 7 / 7
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 23 / 23
• Subtask 7: 26 / 26