Submission #958321

#	Time	Username	Problem	Language	Result	Execution time	Memory
958321		vjudge1	Traffic (IOI10_traffic)	C++17	0 / 100	11 ms	31320 KiB

traffic

#include "traffic.h"
#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define fi first
#define se second
#define pii pair<int, int>
#define pll pair<ll, ll>

const int N = 1000069;
const ll mod = 1e9 + 7;

int tc, ans;
ll sub[N], tot, dp[N];
vector<int> al[N];

void dfs(int x, int p, int P[])
{
    sub[x] += (ll)P[x];
    for(auto z : al[x])
    {
        if(z == p) continue;
        dfs(z, x, P);
        sub[x] += sub[z];
    }
}

void dfs2(int x, int p)
{
    for(auto z : al[x])
    {
        if(z == p) continue;
        dfs2(z, x);
        dp[x] = max(dp[x], sub[z]);
    }
    dp[x] = max(dp[x], tot - sub[x]);
    if(dp[x] < dp[ans]) ans = x;
}

int LocateCentre(int n, int P[], int S[], int D[]) 
{
    int i, j;

    ans = 0;
    for(i = 0; i < n; i++) tot += (ll)P[i];
    
    for(i = 0; i < n-1; i++)
    {
        al[S[i]].push_back(D[i]);
        al[D[i]].push_back(S[i]);
    }
    dfs(0, -1, P);
    dfs2(0, -1);

    return ans;
}

// int main()
// {
//     ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
//     int i, j;

//     int n;
//     cin >> n;
//     tot = n;
//     for(i = 1; i < n; i++)
//     {
//         int u, v;
//         cin >> u >> v;
//         al[u].push_back(v);
//         al[v].push_back(u);
//     }
//     dfs(1, 1);
//     for(i = 1; i <= n; i++) cout << i << " : " << sub[i] << '\n';
// }

Compilation message (stderr)

traffic.cpp: In function 'int LocateCentre(int, int*, int*, int*)':
traffic.cpp:44:12: warning: unused variable 'j' [-Wunused-variable]
   44 |     int i, j;
      |            ^

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