oj.uz

Submission #503746

# Submission time Handle Problem Language Result Execution time Memory
503746 2022-01-08T20:34:20 Z tabr Islands (IOI08_islands) C++17
80 / 100
 552 ms 131076 KB 
#include <bits/stdc++.h>
using namespace std;
#ifdef tabr
#include "library/debug.cpp"
#else
#define debug(...)
#endif

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vector<vector<int>> g(n);
    vector<int> l(n);
    vector<int> e(n);
    for (int i = 0; i < n; i++) {
        int j;
        cin >> j >> l[i];
        j--;
        e[i] = j;
        g[i].emplace_back(i);
        g[j].emplace_back(i);
    }
    for (int i = 0; i < n; i++) {
        if (e[e[i]] == i) {
            l[e[i]] = l[i] = max(l[e[i]], l[i]);
        }
    }
    long long ans = 0;
    vector<int> was(n);
    vector<int> pv(n);
    vector<int> cycle(n);
    for (int i = 0; i < n; i++) {
        if (was[i]) {
            continue;
        }
        int c1 = -1, c2 = -1;
        int sz = 0;
        int dead = -1;
        function<void(int, int)> dfs1 = [&](int v, int pe) {
            was[v] = 1;
            for (auto id : g[v]) {
                if (id == pe) {
                    continue;
                }
                int to = v ^ id ^ e[id];
                if (was[to]) {
                    if (c1 != -1) {
                        continue;
                    }
                    dead = id;
                    c1 = v;
                    c2 = to;
                    debug(c1, c2);
                    cycle[v]++;
                    if (pv[to] != -1) {
                        cycle[pv[to]]--;
                    }
                    continue;
                }
                pv[to] = v;
                dfs1(to, id);
                cycle[v] += cycle[to];
            }
            sz += cycle[v];
        };
        pv[i] = -1;
        dfs1(i, -1);
        vector<long long> d1(sz + 1), d2(sz + 1);
        function<void(int, int, int, long long)> dfs2 = [&](int v, int p, int cnt, long long now) {
            cnt += cycle[v];
            d1[cnt] = max(d1[cnt], now);
            for (auto id : g[v]) {
                int to = v ^ id ^ e[id];
                if (to == p || id == dead) {
                    continue;
                }
                dfs2(to, v, cnt, now + l[id]);
            }
        };
        dfs2(c1, c2, 0, 0);
        swap(d1, d2);
        dfs2(c2, c1, 0, 0);
        swap(d1, d2);
        for (int j = 0; j < sz; j++) {
            d1[j + 1] = max(d1[j + 1], d1[j]);
            d2[j + 1] = max(d2[j + 1], d2[j]);
        }
        long long t = 0;
        function<long long(int, int, long long)> dfs3 = [&](int v, int p, long long now) {
            vector<long long> c;
            for (auto id : g[v]) {
                int to = v ^ id ^ e[id];
                if (to == p || id == dead) {
                    continue;
                }
                c.emplace_back(dfs3(to, v, now + l[id]));
            }
            t = max(t, now);
            if (c.empty()) {
                return now;
            }
            sort(c.rbegin(), c.rend());
            if (c.size() > 1) {
                t = max(t, c[0] + c[1] - 2 * now);
            }
            return c[0];
        };
        dfs3(c1, c2, 0);
        dfs3(c2, c1, 0);
        debug(t);
        debug(d1);
        debug(d2);
        for (int j = 1; j < sz; j++) {
            t = max(t, d1[j] + d2[sz - j] + l[dead]);
        }
        ans += t;
    }
    cout << ans << '\n';
    return 0;
}

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 0 ms 332 KB Output is correct
4 Correct 0 ms 204 KB Output is correct
5 Correct 0 ms 204 KB Output is correct
6 Correct 0 ms 204 KB Output is correct
7 Correct 0 ms 204 KB Output is correct
8 Correct 0 ms 204 KB Output is correct
9 Correct 0 ms 204 KB Output is correct
10 Correct 0 ms 204 KB Output is correct
11 Correct 0 ms 204 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 460 KB Output is correct
2 Correct 1 ms 332 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 460 KB Output is correct
2 Correct 3 ms 844 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 1776 KB Output is correct
2 Correct 25 ms 5808 KB Output is correct
3 Correct 15 ms 2232 KB Output is correct
4 Correct 7 ms 1264 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 31 ms 7488 KB Output is correct
2 Correct 43 ms 11984 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 119 ms 19156 KB Output is correct
2 Correct 159 ms 31372 KB Output is correct
3 Correct 144 ms 48824 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 174 ms 32676 KB Output is correct
2 Correct 287 ms 80604 KB Output is correct
3 Correct 296 ms 91120 KB Output is correct
4 Correct 342 ms 125332 KB Output is correct

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 419 ms 86936 KB Output is correct
2 Runtime error 552 ms 131076 KB Execution killed with signal 9
3 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 309 ms 131076 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -