Submission #944034

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
944034	2024-03-12T07:24:25 Z	wii	Dreaming (IOI13_dreaming)	C++17	Compilation error	0 ms	0 KB

dreaming

#include <bits/stdc++.h>
using namespace std;

#define sz(x) (int)(x).size()
const int MaxN = 1e5 + 5;

template<typename T> bool maximize(T &res, const T &val) { if (res < val) { res = val; return true; } return false; }
template<typename T> bool minimize(T &res, const T &val) { if (val < res) { res = val; return true; } return false; }

const int Inf = 0x3f3f3f3f;

int n, m, l;
vector<int> pref[MaxN], suff[MaxN];
vector<pair<int, int>> adj[MaxN];

int vis[MaxN];
int dep[MaxN], dp[MaxN];
void dfs(int u, int p) {
    vis[u] = true;

    for (auto [v, w]: adj[u]) if (v != p) {
        dep[v] = dep[u] + w;
        dfs(v, u);

        maximize(dp[u], dp[v] + w);
    }

    //cout << "? " << u << " " << dp[u] << endl;
}

int ans;
void reroot(int u, int p) {
    //cout << u << " " << dp[u] << endl;

    minimize(ans, dp[u]);

    for (int i = 0; i < sz(adj[u]); ++i) {
        auto [v, w] = adj[u][i];
        pref[u].emplace_back(dp[v] + w);
        suff[u].emplace_back(dp[v] + w);
    }

    for (int i = 0; i < sz(adj[u]); ++i) {
        auto [v, w] = adj[u][i];
        if (i) maximize(pref[u][i], pref[u][i - 1]);
    }

    for (int i = sz(adj[u]) - 1; i >= 0; --i) {
        auto [v, w] = adj[u][i];
        if (i + 1 < sz(adj[u])) maximize(suff[u][i], suff[u][i + 1]);
    }

    for (int i = 0; i < sz(adj[u]); ++i) {
        auto [v, w] = adj[u][i];
        if (v == p) continue;

        int old = dp[v];
        int nw = max((i ? pref[u][i - 1] : 0), (i + 1 < sz(adj[u]) ? suff[u][i + 1] : 0));

        dp[u] = nw;
        dp[v] = max(dp[u] + w, old);

        reroot(v, u);

        dp[u] = pref[u].back();
        dp[v] = old;
    }
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    n = N;
    m = M;
    l = L;

    for (int i = 0; i < m; ++i) {
        int u = A[i];
        int v = B[i];
        int w = T[i];

        adj[u].emplace_back(v, w);
        adj[v].emplace_back(u, w);
    }

    vector<int> best;
    for (int i = 0; i < n; ++i) if (!vis[i]) {
        dfs(i, i);

        ans = Inf;
        reroot(i, i);

        best.push_back(ans);
    }

    sort(best.begin(), best.end(), greater<int>());
    return best[0] + best[1] + l;
}

Compilation message

dreaming.cpp: In function 'void reroot(int, int)':
dreaming.cpp:44:14: warning: structured binding declaration set but not used [-Wunused-but-set-variable]
   44 |         auto [v, w] = adj[u][i];
      |              ^~~~~~
dreaming.cpp:49:14: warning: structured binding declaration set but not used [-Wunused-but-set-variable]
   49 |         auto [v, w] = adj[u][i];
      |              ^~~~~~
/usr/bin/ld: /tmp/ccd34bFb.o: in function `main':
grader.c:(.text.startup+0xd1): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status