Submission #856815

#	Time	Username	Problem	Language	Result	Execution time	Memory
856815		bkhanh	Two Currencies (JOI23_currencies)	C++14	100 / 100	875 ms	45524 KiB

currencies

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

#define ll long long
#define fi first
#define se second
typedef pair <ll, ll> ii;
const ll N = 1e5 + 99;

struct st
{
    ll s, t, z, w;
};

st qs[N];
ll n, m, q, up[N][20], In[N], Out[N], h[N], cnt;
ll num[N], diff[N], dd[N], ans[N];
ii edg[N];
vector <ll> adj[N];
vector <ii> vt;

void dfs(ll u)
{
    In[u] = ++cnt;
    for (ll v : adj[u])
    {
        if (up[u][0] == v) continue;
        h[v] = h[u] + 1;
        up[v][0] = u;
        for (int i = 1; i <= 16; i++)
        {
            up[v][i] = up[up[v][i - 1]][i - 1];
        }
        dfs(v);
    }
    Out[u] = cnt;
}

void pre(ll u)
{
    for (ll v : adj[u])
    {
        if (up[u][0] == v) continue;
        dd[v] += dd[u];
        pre(v);
    }
}

ll lca(ll u, ll v)
{
    if (h[u] < h[v]) swap(u, v);
    ll k = h[u] - h[v];

    for (int i = 0; (1 << i) <= k; i++)
    {
        if (k >> i & 1)
        {
            u = up[u][i];
        }
    }

    if (u == v) return u;

    k = log2(h[u]);
    for (int i = k; i >= 0; i--)
    {
        if (up[u][i] != up[v][i])
        {
            u = up[u][i];
            v = up[v][i];
        }
    }
    return up[u][0];
}

void update(ll x, ll val)
{
    for (; x <= cnt; x += (x & -x))
    {
        diff[x] += val;
        if (val >= 0) num[x]++;
        else num[x]--;
    }
}

ll getval(ll x)
{
    ll res = 0;
    for (; x > 0; x &= (x - 1))
    {
        res += diff[x];
    }
    return res;
}

ll getnum(ll x)
{
    ll res = 0;
    for (; x > 0; x &= (x - 1))
    {
        res += num[x];
    }
    return res;
}

void solve(ll l, ll r, vector <ll> id)
{
    if (l > r || id.size() == 0) return;

    vector <ll> left, right;
    ll mid = (l + r) / 2;
    for (int i = l; i <= mid; i++)
    {
        auto [c, u] = vt[i - 1];
        update(In[u], c);
        update(Out[u] + 1, -c);
    }

    for (ll i : id)
    {
        ll path = lca(qs[i].s, qs[i].t);
        ll val = getval(In[qs[i].s]) + getval(In[qs[i].t]) - 2 * getval(In[path]);
        if (val <= qs[i].w)
        {
            right.push_back(i);
            ans[i] = max(ans[i], getnum(In[qs[i].s]) + getnum(In[qs[i].t]) - 2 * getnum(In[path]));
        }
        else left.push_back(i);
    }

    solve(mid + 1, r, right);

    for (int i = l; i <= mid; i++)
    {
        auto [c, u] = vt[i - 1];
        update(In[u], -c);
        update(Out[u] + 1,  c);
    }

    if (l != r) solve(l, mid, left);
}

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

    if(fopen("test.inp", "r"))
    {
        freopen("test.inp", "r", stdin);
        freopen("test.out", "w", stdout);
    }

    cin >> n >> m >> q;
    for (int i = 1; i < n; i++)
    {
        cin >> edg[i].fi >> edg[i].se;
        adj[edg[i].fi].push_back(edg[i].se);
        adj[edg[i].se].push_back(edg[i].fi);
    }

    dfs(1);

    for (int i = 1; i <= m; i++)
    {
        ll x, c;
        cin >> x >> c;
        ll res = edg[x].fi;
        if (h[edg[x].fi] < h[edg[x].se]) res = edg[x].se;
        dd[res]++;
        vt.push_back({c, res});
    }

    pre(1);
    sort(vt.begin(), vt.end());
    vector <ll> id;

    for (int i = 1; i <= q; i++)
    {
        cin >> qs[i].s >> qs[i].t >> qs[i].z >> qs[i].w;
        id.push_back(i);
    }

    solve(1, m, id);

    for (int i = 1; i <= q; i++)
    {
        ll path = lca(qs[i].s, qs[i].t);
        ll res = dd[qs[i].s] + dd[qs[i].t] - 2 * dd[path];
        if (res - ans[i] > qs[i].z)
        {
            cout << -1 << '\n';
        }
        else
        {
            cout << qs[i].z - (res - ans[i]) << '\n';
        }
    }
}

Compilation message (stderr)

currencies.cpp: In function 'void solve(long long int, long long int, std::vector<long long int>)':
currencies.cpp:114:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  114 |         auto [c, u] = vt[i - 1];
      |              ^
currencies.cpp:135:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  135 |         auto [c, u] = vt[i - 1];
      |              ^
currencies.cpp: In function 'int main()':
currencies.cpp:151:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  151 |         freopen("test.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
currencies.cpp:152:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  152 |         freopen("test.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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