Submission #854960

#	Time	Username	Problem	Language	Result	Execution time	Memory
854960		thinknoexit	Traffic (IOI10_traffic)	C++17	0 / 100	7 ms	35332 KiB

traffic

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll INF = 1e18;
const int N = 1001000;
pair<ll, int> dp[2][N];
vector<int> adj[N];
int a[N], ans = -1;
ll mn = INF;
void dfs(int v, int p = -1) {
    dp[0][v] = dp[1][v] = { 0, -1 };
    for (auto& x : adj[v]) {
        if (x == p) continue;
        dfs(x, v);
        pair<ll, int> now = { dp[0][x].first + a[x], x };
        dp[1][x] = max(dp[1][x], now);
        if (dp[1][x] > dp[0][x]) swap(dp[1][x], dp[0][x]);
    }
}
void dfs2(int v, int p = -1, ll w = 0) {
    if (max(w, dp[0][v].first) < mn) {
        mn = max(w, dp[0][v].first);
        ans = v;
    }
    for (auto& x : adj[v]) {
        if (x == p) continue;
        if (dp[0][v].second == x) dfs2(x, v, dp[1][v].first + a[v]);
        else dfs2(x, v, dp[0][v].first + a[v]);
    }
}
int LocateCentre(int n, int p[], int s[], int d[]) {
    for (int i = 0;i < n;i++) {
        a[i] = p[i];
    }
    for (int i = 0;i < n - 1;i++) {
        adj[s[i]].push_back(d[i]);
        adj[d[i]].push_back(s[i]);
    }
    dfs(0);
    dfs2(0);
    return ans;
}

• Subtask 1: 0 / 25
• Subtask 2: 0 / 25
• Subtask 3: 0 / 25
• Subtask 4: 0 / 25