oj.uz

Submission #692675

# Submission time Handle Problem Language Result Execution time Memory
692675 2023-02-02T04:13:12 Z sharaelong Ancient Books (IOI17_books) C++17
12 / 100
 71 ms 119496 KB 
#include "books.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;

struct DisjointSet {
    int n;
    vector<int> parent, rank;
    DisjointSet(int _n) : n(_n) {
        parent.resize(n);
        iota(parent.begin(), parent.end(), 0);
        rank.resize(n, 0);
    }

    int find(int u) {
        return parent[u] = (u == parent[u] ? u : find(parent[u]));
    }

    void merge(int u, int v) {
        u = find(u); v = find(v);
        if (u == v) return;
        if (rank[u] > rank[v]) swap(u, v);
        parent[u] = v;
        if (rank[u] == rank[v]) ++rank[v];
    }
};

struct FenwickTree {
    vector<int> tree;
    FenwickTree(int size) {
        tree.resize(size+1, 0);
    }

    int sum(int pos) {
        int ret = 0;
        for (int i=pos+1; i>0; i &= (i-1)) ret += tree[i];
        return ret;
    }

    void add(int pos, int val) {
        for (int i=pos+1; i<tree.size(); i+=(i & -i)) tree[i] += val;
    }
};

const int MAX_N = 1e6 + 1;
const ll INF = 4e18;

DisjointSet dsu(MAX_N);
FenwickTree fen(MAX_N);
bool visited[MAX_N];
vector<int> cycle[MAX_N];
vector<int> adj[MAX_N];
ll dp[MAX_N];

void dfs(int here, int parent = -1) {
    bool merged = false;
    if (parent != -1) {
        int mn = *min_element(cycle[here].begin(), cycle[here].end());
        int mx = *max_element(cycle[here].begin(), cycle[here].end());
        if (fen.sum(mx) - fen.sum(mn) > 0) {
            dsu.merge(here, parent);
            for (int x: cycle[here]) fen.add(x, 1);
            if (cycle[here].size() > cycle[parent].size()) swap(cycle[here], cycle[parent]);
            for (int x: cycle[here]) cycle[parent].push_back(x);
            merged = true;
        }
    }
    
    if (!merged) {
        for (int x: cycle[here]) fen.add(x, 1);
    }
    for (int there: adj[here]) {
        dfs(there, here);
    }
    if (!merged) {
        for (int x: cycle[dsu.find(here)]) fen.add(x, -1);
    }
}

ll minimum_walk(vector<int> p, int s) {
    int n = p.size();
    vector<pii> range;
    ll jump_len = 0;
    for (int i=0; i<n; ++i) {
        if (!visited[i]) {
            int l = i, r = i;
            jump_len += abs(i-p[i]);
            visited[i] = true;
            int x = p[i];
            while (x != i) {
                l = min(l, x);
                r = max(r, x);
                jump_len += abs(x-p[x]);
                visited[x] = true;
                dsu.merge(x, i);
                x = p[x];
            }
            range.push_back({ l+1, i });
            range.push_back({ -r-1, i });
        }
    }
    
    sort(range.begin(), range.end(), [](const pii& a, const pii& b) {
        return abs(a.first) < abs(b.first);
    });
    vector<pii> st;
    for (auto[x, idx]: range) {
        // cout << x << ' ' << idx << endl;
        if (x >= 0) {
            st.push_back({ idx, 1 });
        } else {
            int remove_cnt = 0;
            while (dsu.find(st.back().first) != dsu.find(idx)) {
                dsu.merge(st.back().first, idx);
                remove_cnt++;
                st.pop_back();
            }
            assert(!st.empty() && dsu.find(st.back().first) == dsu.find(idx));
            st.back().second += remove_cnt-1;
            if (st.back().second <= 0) st.pop_back();
        }
    }
    
    vector<pair<pii, int>> dfs_order;
    for (int i=0; i<n; ++i) cycle[dsu.find(i)].push_back(i);
    for (int i=0; i<n; ++i) {
        if (dsu.find(i) == i) {
            dfs_order.push_back({ { cycle[i][0], cycle[i].back() }, i });
        }
    }
    sort(dfs_order.begin(), dfs_order.end());
    
    st.clear();
    vector<int> roots;
    for (int i=0; i<dfs_order.size(); ++i) {
        while (!st.empty() && st.back().first < dfs_order[i].first.first) {
            st.pop_back();
        }
        if (!st.empty()) {
            adj[st.back().second].push_back(dfs_order[i].second);
            // cout << st.back().second << ' ' << dfs_order[i].second << endl;
        }
        if (st.empty()) roots.push_back(dfs_order[i].second);
        st.push_back({ dfs_order[i].first.second, dfs_order[i].second });
    }
    for (int r: roots) dfs(r);

    ll accum = s;
    // for (int i=0; i<n; ++i) {
    //     if (dsu.find(i) == i && cycle[i].size() >= 2) {
    //         ll l = INF, r = INF;
    //         for (int x: cycle[i]) {
    //             if (x <= s) l = min(l, (ll)s-x);
    //             if (x >= s) r = min(r, (ll)x-s);
    //         }
    //         cout << i << ' ' << l << ' ' << r << endl;
    //         if (l > INF/2) accum = max(accum, s+r);
    //         else dp[s-l] = s+r;
    //     }
    // }
    for (int root: roots) {
        if (cycle[dsu.find(root)].size() >= 2) {
        ll l = INF, r = INF;
        for (int x: cycle[root]) {
            if (x <= s) l = min(l, (ll)s-x);
            if (x >= s) r = min(r, (ll)x-s);
        }
        // cout << root << ' ' << l << ' ' << r << endl;
        if (l > INF/2) accum = max(accum, s+r);
        else dp[s-l] = s+r;
        }
    }
    
    ll ans = INF;
    for (int i=0; i<=s; ++i) {
        // cout << i << ' ' << accum << endl;
        ans = min(ans, accum-i);
        accum = max(accum, dp[i]);
    }
    // cout << jump_len << endl;
    return jump_len + 2 * ans;
}

Compilation message

books.cpp: In member function 'void FenwickTree::add(int, int)':
books.cpp:42:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |         for (int i=pos+1; i<tree.size(); i+=(i & -i)) tree[i] += val;
      |                           ~^~~~~~~~~~~~
books.cpp: In function 'll minimum_walk(std::vector<int>, int)':
books.cpp:136:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<std::pair<int, int>, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  136 |     for (int i=0; i<dfs_order.size(); ++i) {
      |                   ~^~~~~~~~~~~~~~~~~

Subtask #1
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 28 ms 58956 KB Output is correct
2 Correct 28 ms 58960 KB Output is correct
3 Correct 28 ms 58984 KB Output is correct
4 Correct 28 ms 59028 KB Output is correct
5 Correct 28 ms 58964 KB Output is correct
6 Correct 30 ms 59048 KB Output is correct
7 Correct 28 ms 58932 KB Output is correct
8 Correct 29 ms 58972 KB Output is correct
9 Correct 29 ms 58960 KB Output is correct
10 Correct 27 ms 58932 KB Output is correct
11 Correct 27 ms 59004 KB Output is correct
12 Correct 28 ms 58964 KB Output is correct
13 Correct 28 ms 58984 KB Output is correct
14 Correct 28 ms 58964 KB Output is correct
15 Correct 34 ms 58980 KB Output is correct
16 Correct 28 ms 58996 KB Output is correct
17 Correct 37 ms 58980 KB Output is correct
18 Correct 31 ms 59012 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 28 ms 58956 KB Output is correct
2 Correct 28 ms 58960 KB Output is correct
3 Correct 28 ms 58984 KB Output is correct
4 Correct 28 ms 59028 KB Output is correct
5 Correct 28 ms 58964 KB Output is correct
6 Correct 30 ms 59048 KB Output is correct
7 Correct 28 ms 58932 KB Output is correct
8 Correct 29 ms 58972 KB Output is correct
9 Correct 29 ms 58960 KB Output is correct
10 Correct 27 ms 58932 KB Output is correct
11 Correct 27 ms 59004 KB Output is correct
12 Correct 28 ms 58964 KB Output is correct
13 Correct 28 ms 58984 KB Output is correct
14 Correct 28 ms 58964 KB Output is correct
15 Correct 34 ms 58980 KB Output is correct
16 Correct 28 ms 58996 KB Output is correct
17 Correct 37 ms 58980 KB Output is correct
18 Correct 31 ms 59012 KB Output is correct
19 Runtime error 71 ms 119496 KB Execution killed with signal 6
20 Halted 0 ms 0 KB -

Subtask #3
0 / 28.0

# Verdict Execution time Memory Grader output
1 Correct 28 ms 58956 KB Output is correct
2 Correct 28 ms 58960 KB Output is correct
3 Correct 28 ms 58984 KB Output is correct
4 Correct 28 ms 59028 KB Output is correct
5 Correct 28 ms 58964 KB Output is correct
6 Correct 30 ms 59048 KB Output is correct
7 Correct 28 ms 58932 KB Output is correct
8 Correct 29 ms 58972 KB Output is correct
9 Correct 29 ms 58960 KB Output is correct
10 Correct 27 ms 58932 KB Output is correct
11 Correct 27 ms 59004 KB Output is correct
12 Correct 28 ms 58964 KB Output is correct
13 Correct 28 ms 58984 KB Output is correct
14 Correct 28 ms 58964 KB Output is correct
15 Correct 34 ms 58980 KB Output is correct
16 Correct 28 ms 58996 KB Output is correct
17 Correct 37 ms 58980 KB Output is correct
18 Correct 31 ms 59012 KB Output is correct
19 Runtime error 71 ms 119496 KB Execution killed with signal 6
20 Halted 0 ms 0 KB -

Subtask #4
0 / 20.0

# Verdict Execution time Memory Grader output
1 Runtime error 71 ms 119488 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #5
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 28 ms 58956 KB Output is correct
2 Correct 28 ms 58960 KB Output is correct
3 Correct 28 ms 58984 KB Output is correct
4 Correct 28 ms 59028 KB Output is correct
5 Correct 28 ms 58964 KB Output is correct
6 Correct 30 ms 59048 KB Output is correct
7 Correct 28 ms 58932 KB Output is correct
8 Correct 29 ms 58972 KB Output is correct
9 Correct 29 ms 58960 KB Output is correct
10 Correct 27 ms 58932 KB Output is correct
11 Correct 27 ms 59004 KB Output is correct
12 Correct 28 ms 58964 KB Output is correct
13 Correct 28 ms 58984 KB Output is correct
14 Correct 28 ms 58964 KB Output is correct
15 Correct 34 ms 58980 KB Output is correct
16 Correct 28 ms 58996 KB Output is correct
17 Correct 37 ms 58980 KB Output is correct
18 Correct 31 ms 59012 KB Output is correct
19 Runtime error 71 ms 119496 KB Execution killed with signal 6
20 Halted 0 ms 0 KB -