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Submission #331387

# Submission time Handle Problem Language Result Execution time Memory
331387 2020-11-28T08:58:59 Z quindecim Islands (IOI08_islands) C++14
90 / 100
 707 ms 131076 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int MOD = 1e9+7;
const int MX = 1e6+10;
const ll INF = 1ll<<60;

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);
    #ifdef NOT_DMOJ
    freopen("input.in", "r", stdin);
    #endif // NOT_DMOJ
    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 17 ms 23916 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 15 ms 23788 KB Output is correct
7 Correct 15 ms 23788 KB Output is correct
8 Correct 16 ms 23788 KB Output is correct
9 Correct 15 ms 23788 KB Output is correct
10 Correct 16 ms 23788 KB Output is correct
11 Correct 15 ms 23788 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23916 KB Output is correct
2 Correct 15 ms 23916 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 23916 KB Output is correct
2 Correct 19 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 31 ms 25964 KB Output is correct
3 Correct 25 ms 24300 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 47 ms 26732 KB Output is correct
2 Correct 47 ms 28324 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 80 ms 30696 KB Output is correct
2 Correct 86 ms 38544 KB Output is correct
3 Correct 131 ms 43144 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 129 ms 37056 KB Output is correct
2 Correct 167 ms 51664 KB Output is correct
3 Correct 194 ms 67536 KB Output is correct
4 Correct 230 ms 71808 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 249 ms 35804 KB Output is correct
2 Correct 544 ms 87240 KB Output is correct
3 Correct 235 ms 46316 KB Output is correct
4 Correct 357 ms 74884 KB Output is correct
5 Correct 312 ms 72448 KB Output is correct
6 Correct 707 ms 50668 KB Output is correct
7 Correct 357 ms 99908 KB Output is correct

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 387 ms 126444 KB Output is correct
2 Correct 341 ms 86636 KB Output is correct
3 Runtime error 442 ms 131076 KB Execution killed with signal 9 (could be triggered by violating memory limits)
4 Halted 0 ms 0 KB -