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Submission #331535

# Submission time Handle Problem Language Result Execution time Memory
331535 2020-11-28T20:22:29 Z quindecim Islands (IOI08_islands) C++14
90 / 100
 686 ms 131076 KB 
#pragma GCC optimize ("Ofast")
#pragma GCC target ("avx2")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int MOD = 1e9+7;
const int MX = 1e6+10;
const ll INF = 0x3f3f3f3f3f3f3f3f;

int n, m, r, a[MX], w[MX];
vector<int> adj[MX];
ll ans, ret;
vector<ll> V, S;
bitset<MX> vv;

inline int cycle(int u) {
    if(vv[u]) return u;
    vv[u] = 1;
    r = cycle(a[u]);
    if(r) {
        V.push_back(u);
        S.push_back(w[u]);
        if(r==u) return 0;
        else return r;
    }
    vv[u] = 0;
    return 0;
}

inline ll dfs(int u) {
    ll mx = 0;
    vv[u] = 1;
    for(int &v : adj[u]) {
        if(!vv[v]) {
            ll r = dfs(v) + w[v];
            ret = max(ret, mx+r);
            mx = max(mx, r);
        }
    }
    return mx;
}

inline void solve(int u) {
    V.clear(); S.clear();
    cycle(u);
    reverse(V.begin(), V.end());
    reverse(S.begin(), S.end());
    for(auto &v : V) v = dfs(v);
    m = V.size();
    for(int i = m-1; i > 0; --i) swap(S[i], S[i-1]);
    for(int i = 1; i < m; ++i) S[i] += S[i-1];
    ll m1 = -INF, m2 = -INF;
    for(int i = 0; i < m; ++i) {
        ret = max(ret, max(m1+S[i]+V[i], m2-S[i]+V[i]+S[m-1]));
        m1 = max(m1, V[i]-S[i]);
        m2 = max(m2, V[i]+S[i]);
    }
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin >> n;
    for(int i = 1; i <= n; ++i) {
        cin >> a[i] >> w[i];
        adj[a[i]].push_back(i);
    }
    for(int i = 1; i <= n; ++i)
        if(!vv[i]) solve(i), ans+=ret, ret = 0;
    cout << ans << "\n";
    return 0;
}

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23788 KB Output is correct
2 Correct 16 ms 23788 KB Output is correct
3 Correct 16 ms 23916 KB Output is correct
4 Correct 16 ms 23788 KB Output is correct
5 Correct 16 ms 23788 KB Output is correct
6 Correct 16 ms 23788 KB Output is correct
7 Correct 16 ms 23788 KB Output is correct
8 Correct 16 ms 23788 KB Output is correct
9 Correct 16 ms 23848 KB Output is correct
10 Correct 16 ms 23788 KB Output is correct
11 Correct 19 ms 23788 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23916 KB Output is correct
2 Correct 16 ms 23936 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 23916 KB Output is correct
2 Correct 17 ms 24172 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 24428 KB Output is correct
2 Correct 28 ms 25964 KB Output is correct
3 Correct 23 ms 24428 KB Output is correct
4 Correct 20 ms 24172 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 35 ms 26732 KB Output is correct
2 Correct 43 ms 28392 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 77 ms 30740 KB Output is correct
2 Correct 83 ms 38544 KB Output is correct
3 Correct 102 ms 43144 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 127 ms 36844 KB Output is correct
2 Correct 158 ms 51536 KB Output is correct
3 Correct 187 ms 67536 KB Output is correct
4 Correct 225 ms 71808 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 242 ms 35876 KB Output is correct
2 Correct 525 ms 87240 KB Output is correct
3 Correct 231 ms 46316 KB Output is correct
4 Correct 303 ms 74832 KB Output is correct
5 Correct 300 ms 72448 KB Output is correct
6 Correct 686 ms 50796 KB Output is correct
7 Correct 348 ms 99784 KB Output is correct

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 378 ms 129900 KB Output is correct
2 Correct 316 ms 86508 KB Output is correct
3 Runtime error 343 ms 131076 KB Execution killed with signal 9 (could be triggered by violating memory limits)
4 Halted 0 ms 0 KB -