Submission #1301261

#	Time	Username	Problem	Language	Result	Execution time	Memory
1301261		Thanhs	Rigged Roads (NOI19_riggedroads)	C++20	9 / 100	1081 ms	327680 KiB

riggedroads

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

#define name "TENBAI"
#define fi first
#define se second
#define int long long
#define endl '\n'
#define setmin(x, y) x = min((x), (y))
#define setmax(x, y) x = max((x), (y))
#define sqr(x) ((x) * (x))
#define all(x) x.begin(), x.end()

mt19937 hdp(chrono::high_resolution_clock::now().time_since_epoch().count());
int rand(int l, int r){return l + ((hdp() % (r - l + 1)) + r - l + 1) % (r - l + 1);}

const int NM = 3e5 + 5;
const int LG = 20;

int n, m, ans[NM], cr, up[NM][LG], par[NM], dep[NM], jump[NM];
pair<int, int> e[NM];
map<pair<int, int>, int> mp;
vector<int> g[NM], siu;

void dfs(int u)
{
    for (int v : g[u])
    {
        g[v].erase(find(all(g[v]), u));
        par[v] = up[v][0] = u;
        dep[v] = dep[u] + 1;
        dfs(v);
    }
}

int lca(int u, int v)
{
    if (dep[u] < dep[v])
        swap(u, v);
    if (dep[u] > dep[v])
    {
        int t = dep[u] - dep[v];
        for (int i = 0; (1 << i) <= t; i++)
            if (t >> i & 1)
                u = up[u][i];
    }
    if (u == v)
        return u;
    for (int i = LG - 1; i >= 0; i--)
        if (up[u][i] != up[v][i])
            u = up[u][i], v = up[v][i];
    return up[u][0];
}

void add(int u, int l)
{
    while (dep[u] > dep[l])
    {
        if (jump[u] == u)
        {
            siu.push_back(mp[{u, par[u]}]);
            jump[u] = jump[l];
            u = par[u];
        }
        else
        {
            int t = jump[u];
            u = t;
            jump[u] = jump[l];
        }
    }
}

void solve()
{
    cin >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        int u, v;
        cin >> e[i].fi >> e[i].se;
        mp[{e[i].fi, e[i].se}] = mp[{e[i].se, e[i].fi}] = i;
    }
    for (int i = 1; i <= n; i++)
        jump[i] = i;
    for (int i = 1; i < n; i++)
    {
        int x;
        cin >> x;
        g[e[x].fi].push_back(e[x].se);
        g[e[x].se].push_back(e[x].fi);
    }
    dfs(1);
    for (int i = 1; i <= n; i++)
        for (int j = 1; j < LG; j++)
            up[i][j] = up[up[i][j - 1]][j - 1];
    for (int i = 1; i <= m; i++)
    {
        // cout << i << ' ' << cr << endl;
        int u = e[i].fi, v = e[i].se;
        if (v == par[u] || u == par[v])
        {
            if (!ans[i])
            {
                ans[i] = ++cr;
                int x = (dep[u] > dep[v] ? u : v);
                jump[x] = jump[par[x]];
            }
        }
        else
        {
            int l = lca(u, v);
            add(u, l);
            add(v, l);
            sort(all(siu));
            for (int t : siu)
                ans[t] = ++cr;
            ans[i] = ++cr;
            siu.clear();
        }
    }
    for (int i = 1; i <= m; i++)
        cout << ans[i] << ' ';
}

signed main()
{
    if (fopen("in.txt", "r")) 
    {
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
    }
    else if (fopen(name".inp", "r"))
    {
        freopen(name".inp", "r", stdin);
        freopen(name".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
    int tc = 1; 
    // cin >> tc;
    while (tc--)
        solve();
}

Compilation message (stderr)

riggedroads.cpp: In function 'int main()':
riggedroads.cpp:129:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  129 |         freopen("in.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
riggedroads.cpp:130:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  130 |         freopen("out.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
riggedroads.cpp:134:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  134 |         freopen(name".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
riggedroads.cpp:135:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  135 |         freopen(name".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 8
• Subtask 2: 0 / 19
• Subtask 3: 9 / 9
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 12
• Subtask 7: 0 / 32