Submission #826967

#	Time	Username	Problem	Language	Result	Execution time	Memory
826967		Hanksburger	Two Currencies (JOI23_currencies)	C++17	28 / 100	215 ms	35568 KiB

currencies

#include <bits/stdc++.h>
using namespace std;
long long U[100005], V[100005], W[100005], par[100005][20], depth[100005], sum[100005];
vector<pair<long long, long long> > adj[100005];
void dfs(long long u, long long p)
{
    par[u][0]=p;
    for (long long i=1; i<20; i++)
        par[u][i]=par[par[u][i-1]][i-1];
    for (long long i=0; i<adj[u].size(); i++)
    {
        long long v=adj[u][i].first, w=adj[u][i].second;
        if (v==p)
            continue;
        depth[v]=depth[u]+1;
        sum[v]=sum[u]+w;
        dfs(v, u);
    }
 }
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    long long n, m, q, val;
    cin >> n >> m >> q;
    for (long long i=1; i<n; i++)
        cin >> U[i] >> V[i];
    for (long long i=1; i<=m; i++)
    {
        long long x, y;
        cin >> x >> y;
        W[x]++;
        val=y;
    }
    for (long long i=1; i<n; i++)
    {
        adj[U[i]].push_back({V[i], W[i]});
        adj[V[i]].push_back({U[i], W[i]});
    }
    dfs(1, 1);
    for (long long i=1; i<=q; i++)
    {
        long long a, b, c, d, curA, curB;
        cin >> a >> b >> c >> d;
        if (depth[a]<depth[b])
            swap(a, b);
        curA=a, curB=b;
        for (long long j=19; j>=0; j--)
            if ((depth[a]-depth[b])&(1<<j))
                curA=par[curA][j];
        for (long long j=19; j>=0; j--)
        {
            if (par[curA][j]!=par[curB][j])
            {
                curA=par[curA][j];
                curB=par[curB][j];
            }
        }
        if (curA!=curB)
        {
            curA=par[curA][0];
            curB=par[curB][0];
        }
        cout << max(-1LL, c-max(0LL, sum[a]+sum[b]-sum[curA]*2-d/val)) << '\n';
    }
}

Compilation message (stderr)

currencies.cpp: In function 'void dfs(long long int, long long int)':
currencies.cpp:10:26: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |     for (long long i=0; i<adj[u].size(); i++)
      |                         ~^~~~~~~~~~~~~~
currencies.cpp: In function 'int main()':
currencies.cpp:65:65: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
   65 |         cout << max(-1LL, c-max(0LL, sum[a]+sum[b]-sum[curA]*2-d/val)) << '\n';
      |                                                                ~^~~~

• Subtask 1: 0 / 10
• Subtask 2: 28 / 28
• Subtask 3: 0 / 30
• Subtask 4: 0 / 32