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Submission #331536

# Submission time Handle Problem Language Result Execution time Memory
331536 2020-11-28T20:28:30 Z quindecim Islands (IOI08_islands) C++14
90 / 100
 727 ms 131072 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, a[MX], w[MX];
vector<int> adj[MX];
ll ans, ret;
vector<ll> V, S;
bool vv[MX];

inline int cycle(int u) {
    if(vv[u]) return u;
    vv[u] = 1;
    int 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 20 ms 23788 KB Output is correct
2 Correct 17 ms 23788 KB Output is correct
3 Correct 17 ms 23916 KB Output is correct
4 Correct 17 ms 23788 KB Output is correct
5 Correct 17 ms 23788 KB Output is correct
6 Correct 17 ms 23808 KB Output is correct
7 Correct 17 ms 23788 KB Output is correct
8 Correct 17 ms 23788 KB Output is correct
9 Correct 17 ms 23808 KB Output is correct
10 Correct 17 ms 23800 KB Output is correct
11 Correct 17 ms 23788 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 23936 KB Output is correct
2 Correct 17 ms 23916 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 23916 KB Output is correct
2 Correct 21 ms 24172 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 24428 KB Output is correct
2 Correct 30 ms 25964 KB Output is correct
3 Correct 24 ms 24428 KB Output is correct
4 Correct 21 ms 24136 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 26856 KB Output is correct
2 Correct 46 ms 28520 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 78 ms 30828 KB Output is correct
2 Correct 84 ms 38792 KB Output is correct
3 Correct 107 ms 43400 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 139 ms 37228 KB Output is correct
2 Correct 170 ms 52048 KB Output is correct
3 Correct 198 ms 68048 KB Output is correct
4 Correct 248 ms 72448 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 263 ms 36700 KB Output is correct
2 Correct 589 ms 88136 KB Output is correct
3 Correct 238 ms 46956 KB Output is correct
4 Correct 318 ms 75216 KB Output is correct
5 Correct 324 ms 73088 KB Output is correct
6 Correct 727 ms 51476 KB Output is correct
7 Correct 361 ms 100808 KB Output is correct

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 373 ms 125292 KB Output is correct
2 Correct 382 ms 87532 KB Output is correct
3 Runtime error 349 ms 131072 KB Execution killed with signal 9 (could be triggered by violating memory limits)
4 Halted 0 ms 0 KB -