oj.uz

Submission #914525

# Submission time Handle Problem Language Result Execution time Memory
914525 2024-01-22T10:05:46 Z sleepntsheep One-Way Streets (CEOI17_oneway) C++17
100 / 100
 313 ms 47188 KB 
#include <stack>
#include <iostream>
#include <fstream>
#include <iomanip>
#include <cmath>
#include <cassert>
#include <cstring>
#include <vector>
#include <algorithm>
#include <deque>
#include <set>
#include <utility>
#include <array>
#include <complex>

using namespace std;
#define ALL(x) begin(x), end(x)
#define ShinLena cin.tie(nullptr)->sync_with_stdio(false);
#define N 200005

int n, m, p;
basic_string<pair<int, int>> g[N];

int tin[N], low[N], timer; char ans[N];
int grp[N], twoedgecc;

stack<int> sd;

void tarjan(int u, int p)
{
    tin[u] = low[u] = ++timer;
    sd.push(u);

    for (auto [v, _] : g[u])
    {
        if (v == p)
        {
            p = -1;
            continue;
        }
        if (!tin[v])
            tarjan(v, u);
        low[u] = min(low[u], low[v]);
    }

    if (tin[u] == low[u])
    {
        int v;
        do
        {
            grp[v = sd.top()] = twoedgecc;
            sd.pop();
        }
        while (v != u);
        ++twoedgecc;
    }
}

basic_string<pair<int, int> > G[N];

int aux[N], sz[N], ch[N], ci[N], P[20][N], hv[N], hveid[N], dep[N];

void dfs(int u, int p)
{
    sz[u] = 1;
    P[0][u] = p;
    for (int j = 1; j < 18; ++j) P[j][u] = P[j-1][P[j-1][u]];
    int hvsz = -1;
    for (auto [v, _] : G[u]) if (v != p)
    {
        dep[v] = dep[u] + 1;
        dfs(v, u); sz[u] += sz[v];
        if (sz[v] > hvsz) hv[u] = v, hvsz = sz[v], hveid[u] = _;
    }
}

int ctimer;
void hld(int u, int h, int pd)
{
    ci[u] = ctimer++; ch[u] = h;
    aux[u] = pd;
    if (hv[u]) hld(hv[u], h, hveid[u]);
    for (auto [v, _] : G[u]) if (v != P[0][u] and v != hv[u]) hld(v, v, _);
    hv[u] = -1;
}

int lca(int u, int v)
{
    if (dep[u] < dep[v]) swap(v, u);
    int dt = dep[u] - dep[v];
    for(int j=18;j--;)if(dt&(1<<j))u=P[j][u];
    if(u==v)return u;
    for(int j=18;j--;)if(P[j][u]-P[j][v])u=P[j][u],v=P[j][v];
    return P[0][u];
}

char whatt[N<<1], lz[N<<1];
void _push(int v, int l, int r)
{
    if (lz[v])
    {
        whatt[v]=lz[v];
        if (l-r)
        {
            auto m=(l+r)/2,vl=v+1,vr=v+(m-l+1)*2;
            lz[vl]=lz[vr]=lz[v];
        }
        lz[v]=0;
    }
}

void _set(int v, int l, int r,int x,int y,int k)
{
    _push(v,l,r);
    if(r<x or y<l)return;
    if(x<=l and r<=y){lz[v]=k;_push(v,l,r);return;}
    auto m=(l+r)/2,vl=v+1,vr=v+(m-l+1)*2;
    _set(vl,l,m,x,y,k);_set(vr,m+1,r,x,y,k);
}

char _qry(int v,int l, int r, int p)
{
    _push(v,l,r);
    if(l==r)return whatt[v];
    auto m=(l+r)/2,vl=v+1,vr=v+(m-l+1)*2;
    if(p<=m)return _qry(vl,l,m,p); return _qry(vr,m+1,r,p);
}

void updup(int u, int a, int d)
{
    //cout << "UPDUP " << u << ' ' << a << ' ' << char(d)<<'\n';
    for (; ch[u] != ch[a]; u = P[0][ch[u]])
        _set(0, 0, ctimer, ci[ch[u]], ci[u], d);
    _set(0, 0, ctimer, ci[a], ci[u], d);
}

int main()
{
    ShinLena;
    cin >> n >> m;
    for (int u, v, i = 1; i <= m; ++i)
        cin >> u >> v, g[u].push_back({v, i}), g[v].push_back({u, -i}), ans[i] = 'B';

    int Trees = 0;
    for (int i = 1; i <= n; ++i) if (!tin[i]) tarjan(i, -1), ++Trees;

    for (int u = 1; u <= n; ++u)
        for (auto [v, eid] : g[u])
            if (eid > 0 and grp[u] != grp[v])
                G[grp[u]].push_back({grp[v], eid}), G[grp[v]].push_back({grp[u], -eid});

    for (int i = 0; i < twoedgecc; ++i)
        sort(ALL(G[i])), G[i].resize(unique(ALL(G[i])) - G[i].begin());

    
    for (int i = 0; i < twoedgecc; ++i) if (!sz[i]) dfs(i, -1), hld(i, i, 0);

    _set(0, 0, ctimer, 0, ctimer, 'B');

    cin >> p;
    for (int x, y, i = 0; i < p; ++i)
    {
        cin >> x >> y;
        if ((x = grp[x]) == (y = grp[y])) continue;
        int a = lca(x, y);
        int X = _qry(0,0,ctimer,ci[a]);
        updup(x, a, 'L');
        updup(y, a, 'R');
        _set(0,0,ctimer,ci[a],ci[a],X);
    }

    for (int i = 0; i < twoedgecc; ++i)
    {
        if (aux[i] == 0) continue;
        ans[abs(aux[i])] = _qry(0,0,ctimer,ci[i]);
        if (aux[i] < 0)
        {
            aux[i] *= -1;
            if (ans[aux[i]] == 'L') ans[aux[i]] = 'R';
            else if (ans[aux[i]] == 'R') ans[aux[i]] = 'L';
        }
    }

    cout << (ans+1);


    return 0;
}

Compilation message

oneway.cpp: In function 'char _qry(int, int, int, int)':
oneway.cpp:127:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  127 |     if(p<=m)return _qry(vl,l,m,p); return _qry(vr,m+1,r,p);
      |     ^~
oneway.cpp:127:36: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  127 |     if(p<=m)return _qry(vl,l,m,p); return _qry(vr,m+1,r,p);
      |                                    ^~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 31068 KB Output is correct
2 Correct 7 ms 31036 KB Output is correct
3 Correct 7 ms 31068 KB Output is correct
4 Correct 8 ms 31068 KB Output is correct
5 Correct 8 ms 31068 KB Output is correct
6 Correct 7 ms 31068 KB Output is correct
7 Correct 8 ms 31068 KB Output is correct
8 Correct 8 ms 31064 KB Output is correct
9 Correct 9 ms 31068 KB Output is correct
10 Correct 8 ms 31068 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 31068 KB Output is correct
2 Correct 7 ms 31036 KB Output is correct
3 Correct 7 ms 31068 KB Output is correct
4 Correct 8 ms 31068 KB Output is correct
5 Correct 8 ms 31068 KB Output is correct
6 Correct 7 ms 31068 KB Output is correct
7 Correct 8 ms 31068 KB Output is correct
8 Correct 8 ms 31064 KB Output is correct
9 Correct 9 ms 31068 KB Output is correct
10 Correct 8 ms 31068 KB Output is correct
11 Correct 31 ms 35164 KB Output is correct
12 Correct 35 ms 35744 KB Output is correct
13 Correct 38 ms 36688 KB Output is correct
14 Correct 47 ms 37208 KB Output is correct
15 Correct 49 ms 39420 KB Output is correct
16 Correct 75 ms 39720 KB Output is correct
17 Correct 87 ms 42484 KB Output is correct
18 Correct 65 ms 39760 KB Output is correct
19 Correct 71 ms 44412 KB Output is correct
20 Correct 34 ms 35412 KB Output is correct
21 Correct 37 ms 35412 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 31068 KB Output is correct
2 Correct 7 ms 31036 KB Output is correct
3 Correct 7 ms 31068 KB Output is correct
4 Correct 8 ms 31068 KB Output is correct
5 Correct 8 ms 31068 KB Output is correct
6 Correct 7 ms 31068 KB Output is correct
7 Correct 8 ms 31068 KB Output is correct
8 Correct 8 ms 31064 KB Output is correct
9 Correct 9 ms 31068 KB Output is correct
10 Correct 8 ms 31068 KB Output is correct
11 Correct 31 ms 35164 KB Output is correct
12 Correct 35 ms 35744 KB Output is correct
13 Correct 38 ms 36688 KB Output is correct
14 Correct 47 ms 37208 KB Output is correct
15 Correct 49 ms 39420 KB Output is correct
16 Correct 75 ms 39720 KB Output is correct
17 Correct 87 ms 42484 KB Output is correct
18 Correct 65 ms 39760 KB Output is correct
19 Correct 71 ms 44412 KB Output is correct
20 Correct 34 ms 35412 KB Output is correct
21 Correct 37 ms 35412 KB Output is correct
22 Correct 236 ms 42320 KB Output is correct
23 Correct 313 ms 40368 KB Output is correct
24 Correct 301 ms 39912 KB Output is correct
25 Correct 215 ms 47188 KB Output is correct
26 Correct 258 ms 42320 KB Output is correct
27 Correct 298 ms 40532 KB Output is correct
28 Correct 26 ms 33360 KB Output is correct
29 Correct 66 ms 34920 KB Output is correct
30 Correct 84 ms 35048 KB Output is correct
31 Correct 48 ms 35412 KB Output is correct
32 Correct 153 ms 38624 KB Output is correct