oj.uz

Submission #503786

# Submission time Handle Problem Language Result Execution time Memory
503786 2022-01-08T22:21:45 Z tabr Islands (IOI08_islands) C++17
67 / 100
 2000 ms 76892 KB 
#include <bits/stdc++.h>
using namespace std;
#ifdef tabr
#include "library/debug.cpp"
#else
#define debug(...)
#endif

struct dsu {
    vector<int> p;
    vector<int> sz;
    int n;

    dsu(int _n) : n(_n) {
        p.resize(n);
        iota(p.begin(), p.end(), 0);
        sz.assign(n, 1);
    }

    inline int get(int x) {
        if (p[x] == x) {
            return x;
        } else {
            return p[x] = get(p[x]);
        }
    }

    inline bool unite(int x, int y) {
        x = get(x);
        y = get(y);
        if (x == y) {
            return false;
        }
        if (sz[x] > sz[y]) {
            swap(x, y);
        }
        p[x] = y;
        sz[y] += sz[x];
        return true;
    }

    inline bool same(int x, int y) {
        return (get(x) == get(y));
    }
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vector<int> l(n);
    vector<int> nxt(n);
    vector<int> deg(n);
    dsu uf(n);
    for (int i = 0; i < n; i++) {
        int j;
        cin >> j >> l[i];
        j--;
        uf.unite(i, j);
        nxt[i] = j;
        deg[i]++;
        deg[j]++;
    }
    vector<vector<int>> vs(n);
    for (int i = 0; i < n; i++) {
        vs[uf.get(i)].emplace_back(i);
    }
    long long ans = 0;
    vector<long long> mx(n);
    vector<int> cycle(n);
    vector<int> was(n);
    for (int i = 0; i < n; i++) {
        if (i != uf.get(i)) {
            continue;
        }
        int c = i;
        while (!was[c]) {
            was[c] = 1;
            c = nxt[c];
        }
        cycle[c] = 1;
        int u = nxt[c];
        while (u != c) {
            cycle[u] = 1;
            u = nxt[u];
        }
        queue<int> que;
        for (int j : vs[i]) {
            if (deg[j] == 1) {
                que.emplace(j);
            }
        }
        long long t = 0;
        while (!que.empty()) {
            int v = que.front();
            que.pop();
            int to = nxt[v];
            t = max(t, mx[to] + mx[v] + l[v]);
            mx[to] = max(mx[to], mx[v] + l[v]);
            if (!cycle[to]) {
                que.emplace(to);
            }
        }
        vector<int> x;
        x.emplace_back(c);
        u = nxt[c];
        while (u != c) {
            x.emplace_back(u);
            u = nxt[u];
        }
        deque<pair<int, long long>> deq;
        deq.emplace_back(0, 0);
        long long y = l[c];
        int sz = (int) x.size();
        for (int jj = 1; jj < sz * 2; jj++) {
            int j = jj % sz;
            if (x[deq.front().first] == x[j]) {
                deq.pop_front();
            }
            t = max(t, y + mx[x[j]] - deq.front().second);
            long long z = y - mx[x[j]];
            while (!deq.empty() && deq.back().second >= z) {
                deq.pop_back();
            }
            y += l[x[j]];
            deq.emplace_back(j, z);
        }
        ans += t;
    }
    cout << ans << '\n';
    return 0;
}

Subtask #1
30.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Incorrect 0 ms 204 KB Output isn't 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 1 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 332 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 332 KB Output is correct
2 Correct 2 ms 588 KB Output is correct

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 1228 KB Output is correct
2 Correct 9 ms 2692 KB Output is correct
3 Correct 14 ms 1612 KB Output is correct
4 Incorrect 5 ms 972 KB Output isn't correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 3632 KB Output is correct
2 Correct 24 ms 6944 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 45 ms 13148 KB Output is correct
2 Correct 48 ms 16452 KB Output is correct
3 Correct 65 ms 19028 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 85 ms 25932 KB Output is correct
2 Correct 107 ms 33852 KB Output is correct
3 Correct 119 ms 43160 KB Output is correct
4 Correct 153 ms 48180 KB Output is correct

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 219 ms 66964 KB Output is correct
2 Correct 260 ms 76892 KB Output is correct
3 Correct 172 ms 51140 KB Output is correct
4 Correct 220 ms 68464 KB Output is correct
5 Correct 231 ms 69732 KB Output is correct
6 Execution timed out 2076 ms 61764 KB Time limit exceeded
7 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 231 ms 63032 KB Output is correct
2 Incorrect 222 ms 63008 KB Output isn't correct
3 Halted 0 ms 0 KB -