Submission #1121422

#	Time	Username	Problem	Language	Result	Execution time	Memory
1121422		namprozz	Race (IOI11_race)	C++14	Compilation error	0 ms	0 KiB

race

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

const int MAXN = 200005;

int n;
ll k;
vector<pair<int, ll>> adj[MAXN];

int child[MAXN];
bool marked[MAXN];
void countChild(int u, int p)
{
    child[u] = 1;
    for(auto [v, w] : adj[u])
    {
        if(v == p or marked[v])
            continue;
        countChild(v, u);
        child[u] += child[v];
    }
}

int findCentroid(int u, int p, int n)
{
    for(auto [v, w] : adj[u])
    {
        if(v == p or marked[v])
            continue;
        if(child[v] > n / 2)
        {
            return findCentroid(v, u, n);
        }
    }
    return u;
}

int res = INT_MAX;
map<ll, int> dp;
void dfs(int u, int p, int d, ll tong)
{
    if(tong > k)
        return;
    if(dp.count(k - tong))
    {
        res = min(res, d + dp[k - tong]);
    }

    for(auto [v, w] : adj[u])
    {
        if(v == p or marked[v])
            continue;
        dfs(v, u, d + 1, tong + w);
    }

    if(dp.count(tong))
    {
        dp[tong] = min(dp[tong], d);
    }
    else
    {
        dp[tong] = d;
    }
}

void decomp(int u)
{
    countChild(u, -1);
    int c = findCentroid(u, -1, child[u]);
    marked[c] = true;

    dp.clear();
    dp[0] = 0;
    dfs(c, -1, 0, 0);

    for(auto [v, w] : adj[c])
    {
        if(marked[v])
            continue;
        decomp(v);
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    cin >> n >> k;
    for(int i = 0; i < n - 1; i++)
    {
        int u, v;
        ll w;
        cin >> u >> v >> w;

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

    fill(marked, marked + n, false);
    decomp(0);
    if(res == INT_MAX)
    {
        cout << "-1" << '\n';
    }
    else
    {
        cout << res << '\n';
    }
}

Compilation message (stderr)

race.cpp: In function 'void countChild(int, int)':
race.cpp:16:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   16 |     for(auto [v, w] : adj[u])
      |              ^
race.cpp: In function 'int findCentroid(int, int, int)':
race.cpp:27:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   27 |     for(auto [v, w] : adj[u])
      |              ^
race.cpp: In function 'void dfs(int, int, int, long long int)':
race.cpp:50:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   50 |     for(auto [v, w] : adj[u])
      |              ^
race.cpp: In function 'void decomp(int)':
race.cpp:77:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   77 |     for(auto [v, w] : adj[c])
      |              ^
/usr/bin/ld: /tmp/cczE4NJg.o: in function `main':
race.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccFkp36j.o:grader.cpp:(.text.startup+0x0): first defined here
/usr/bin/ld: /tmp/ccFkp36j.o: in function `main':
grader.cpp:(.text.startup+0x28): undefined reference to `best_path(int, int, int (*) [2], int*)'
collect2: error: ld returned 1 exit status