oj.uz

답안 #650690

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
650690 2022-10-14T17:16:07 Z Spade1 Islands (IOI08_islands) C++14
80 / 100
 494 ms 131072 KB 
#include<bits/stdc++.h>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define ll long long
#define ld long double
#define st first
#define nd second
#define pb push_back
#define INF INT_MAX
using namespace std;

const int N = 1e6 + 2;

vector<pair<int, pii>> adj[N];
bool vis[N];
int cycle;

vector<pll> v;
ll dp[N], qs[N], ans, cur;

pll dfs2(int i, int prt1, int prt2) {
    ll mx_w = 0, mx = i;
    for (auto [j, w] : adj[i]) {
        if (j == prt1 || j == prt2) continue;
        pll ret = dfs2(j, i, 0);
        if (ret.nd + w.nd > mx_w) {
            mx_w = ret.nd + w.nd;
            mx = ret.st;
        }
    }
    return {mx, mx_w};
}

ll dfs3(int i, int prt1, int prt2, int prt3) {
    ll mx = 0;
    for (auto [j, w] : adj[i]) {
        if (j == prt1 || j == prt2 || j == prt3) continue;
        mx = max(mx, dfs3(j, i, prt2, prt3) + w.nd);
    }
    return mx;
}

int dfs(int i, int ed, int prt) {
    if (vis[i]) {
        cycle = prt;
        return i;
    }
    vis[i] = 1;
    int ret = 0, K, W;
    for (auto [j, w] : adj[i]) {
        if (j == prt && ed == w.st) continue;
        if (ret != 0 && vis[j]) continue;
        int k = dfs(j, w.st, i);
        if (k) {
            ret = k;
            K = j;
            W = w.nd;
        }
    }
    if (ret == i) {
        auto [val, w] = dfs2(i, K, cycle);
        cur = max(cur, dfs3(val, 0, K, cycle));
        v.pb({w, W});
        return 0;
    }
    else if (ret) {
        auto [val, w] = dfs2(i, prt, K);
        ll k = dfs3(val, 0, prt, K);
        cur = max(cur, k);
        v.pb({w, W});
    }
    return ret;
}

void solve() {
    int n; cin >> n;
    for (int i = 1; i <= n; ++i) {
        int b, w; cin >> b >> w;
        adj[i].pb({b ,{i, w}});
        adj[b].pb({i, {i, w}});
    }

    for (int i = 1; i <= n; ++i) {
        if (vis[i]) continue;
        dfs(i, 0, 0);
        int m = v.size();
        for (int j = 0; j <= m+1; ++j) qs[j] = 0, dp[j] = 0;
        for (int j = 1; j <= m; ++j) {
            qs[j] = qs[j-1] + v[j-1].nd;
            dp[j] = qs[j] + v[j-1].st;
        }
        for (int j = m-1; j > 0; --j) dp[j] = max(dp[j], dp[j+1]);
        for (int j = 1; j < m; ++j) {
            cur = max(cur, v[j-1].st - qs[j] + dp[j+1]);
        }
        for (int j = 0; j <= m+1; ++j) dp[j] = 0;
        for (int j = m; j >= 1; --j) {
            dp[j] = qs[j] + v[j-1].st;
        }
        for (int j = 2; j <= m; ++j) dp[j] = max(dp[j], dp[j-1]);
        for (int j = 2; j <= m; ++j) {
            cur = max(cur, qs[m] + v[j-1].st - qs[j] + dp[j-1]);
        }
        ans += cur;
        v.clear();
        cur = 0, cycle = 0;
    }
    cout << ans << '\n';
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(NULL);
    int t = 1;
//    cin >> t;
    while (t--) {
        solve();
    }
}

Compilation message

islands.cpp: In function 'std::pair<long long int, long long int> dfs2(int, int, int)':
islands.cpp:23:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   23 |     for (auto [j, w] : adj[i]) {
      |               ^
islands.cpp: In function 'long long int dfs3(int, int, int, int)':
islands.cpp:36:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   36 |     for (auto [j, w] : adj[i]) {
      |               ^
islands.cpp: In function 'int dfs(int, int, int)':
islands.cpp:50:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   50 |     for (auto [j, w] : adj[i]) {
      |               ^
islands.cpp:61:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   61 |         auto [val, w] = dfs2(i, K, cycle);
      |              ^
islands.cpp:67:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   67 |         auto [val, w] = dfs2(i, prt, K);
      |              ^
islands.cpp:62:28: warning: 'K' may be used uninitialized in this function [-Wmaybe-uninitialized]
   62 |         cur = max(cur, dfs3(val, 0, K, cycle));
      |                        ~~~~^~~~~~~~~~~~~~~~~~

Subtask #1
33.0 / 33.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 12 ms 23892 KB Output is correct
4 Correct 12 ms 23784 KB Output is correct
5 Correct 13 ms 23812 KB Output is correct
6 Correct 17 ms 23728 KB Output is correct
7 Correct 16 ms 23724 KB Output is correct
8 Correct 14 ms 23764 KB Output is correct
9 Correct 13 ms 23752 KB Output is correct
10 Correct 13 ms 23764 KB Output is correct
11 Correct 12 ms 23764 KB Output is correct

Subtask #2
3.0 / 3.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 23940 KB Output is correct
2 Correct 13 ms 23764 KB Output is correct

Subtask #3
4.0 / 4.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 23860 KB Output is correct
2 Correct 14 ms 24276 KB Output is correct

Subtask #4
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 23 ms 24828 KB Output is correct
2 Correct 29 ms 27860 KB Output is correct
3 Correct 21 ms 24660 KB Output is correct
4 Correct 18 ms 24300 KB Output is correct

Subtask #5
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 37 ms 29252 KB Output is correct
2 Correct 47 ms 30944 KB Output is correct

Subtask #6
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 92 ms 35528 KB Output is correct
2 Correct 92 ms 43352 KB Output is correct
3 Correct 115 ms 58560 KB Output is correct

Subtask #7
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 136 ms 42548 KB Output is correct
2 Correct 192 ms 77820 KB Output is correct
3 Correct 217 ms 84288 KB Output is correct
4 Correct 263 ms 117000 KB Output is correct

Subtask #8
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 346 ms 67828 KB Output is correct
2 Runtime error 494 ms 131072 KB Execution killed with signal 9
3 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 345 ms 131072 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -