oj.uz

Submission #914549

# Submission time Handle Problem Language Result Execution time Memory
914549 2024-01-22T10:26:42 Z sleepntsheep One-Way Streets (CEOI17_oneway) C++17
100 / 100
 317 ms 47420 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, _);
}
 
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);
}
 
char final_2_last[N];
char _build(int v, int l, int r)
{
    _push(v,l,r);
    if (l == r)
        return final_2_last[l] = whatt[v];
    auto m=(l+r)/2,vl=v+1,vr=v+(m-l+1)*2;
    _build(vl, l, m);
    _build(vr, m+1, r);
}
 
void updup(int u, int a, int d)
{
    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';
 
    for (int i = 1; i <= n; ++i) if (!tin[i]) tarjan(i, -1);
 
    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);
    }
 
    //_build(0, 0, ctimer);
    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:119:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  119 |     if(p<=m)return _qry(vl,l,m,p); return _qry(vr,m+1,r,p);
      |     ^~
oneway.cpp:119:36: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  119 |     if(p<=m)return _qry(vl,l,m,p); return _qry(vr,m+1,r,p);
      |                                    ^~~~~~
oneway.cpp: In function 'char _build(int, int, int)':
oneway.cpp:130:11: warning: control reaches end of non-void function [-Wreturn-type]
  130 |     _build(vr, m+1, r);
      |     ~~~~~~^~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 33368 KB Output is correct
2 Correct 7 ms 33372 KB Output is correct
3 Correct 8 ms 33372 KB Output is correct
4 Correct 7 ms 33372 KB Output is correct
5 Correct 7 ms 33452 KB Output is correct
6 Correct 7 ms 33624 KB Output is correct
7 Correct 8 ms 33368 KB Output is correct
8 Correct 9 ms 33368 KB Output is correct
9 Correct 8 ms 33372 KB Output is correct
10 Correct 8 ms 33372 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 33368 KB Output is correct
2 Correct 7 ms 33372 KB Output is correct
3 Correct 8 ms 33372 KB Output is correct
4 Correct 7 ms 33372 KB Output is correct
5 Correct 7 ms 33452 KB Output is correct
6 Correct 7 ms 33624 KB Output is correct
7 Correct 8 ms 33368 KB Output is correct
8 Correct 9 ms 33368 KB Output is correct
9 Correct 8 ms 33372 KB Output is correct
10 Correct 8 ms 33372 KB Output is correct
11 Correct 31 ms 37456 KB Output is correct
12 Correct 34 ms 38112 KB Output is correct
13 Correct 37 ms 38876 KB Output is correct
14 Correct 42 ms 39504 KB Output is correct
15 Correct 61 ms 39628 KB Output is correct
16 Correct 69 ms 39764 KB Output is correct
17 Correct 89 ms 42452 KB Output is correct
18 Correct 67 ms 39928 KB Output is correct
19 Correct 75 ms 44368 KB Output is correct
20 Correct 34 ms 37824 KB Output is correct
21 Correct 39 ms 37212 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 33368 KB Output is correct
2 Correct 7 ms 33372 KB Output is correct
3 Correct 8 ms 33372 KB Output is correct
4 Correct 7 ms 33372 KB Output is correct
5 Correct 7 ms 33452 KB Output is correct
6 Correct 7 ms 33624 KB Output is correct
7 Correct 8 ms 33368 KB Output is correct
8 Correct 9 ms 33368 KB Output is correct
9 Correct 8 ms 33372 KB Output is correct
10 Correct 8 ms 33372 KB Output is correct
11 Correct 31 ms 37456 KB Output is correct
12 Correct 34 ms 38112 KB Output is correct
13 Correct 37 ms 38876 KB Output is correct
14 Correct 42 ms 39504 KB Output is correct
15 Correct 61 ms 39628 KB Output is correct
16 Correct 69 ms 39764 KB Output is correct
17 Correct 89 ms 42452 KB Output is correct
18 Correct 67 ms 39928 KB Output is correct
19 Correct 75 ms 44368 KB Output is correct
20 Correct 34 ms 37824 KB Output is correct
21 Correct 39 ms 37212 KB Output is correct
22 Correct 260 ms 42352 KB Output is correct
23 Correct 312 ms 40488 KB Output is correct
24 Correct 317 ms 39828 KB Output is correct
25 Correct 242 ms 47420 KB Output is correct
26 Correct 252 ms 42068 KB Output is correct
27 Correct 316 ms 40580 KB Output is correct
28 Correct 27 ms 35416 KB Output is correct
29 Correct 56 ms 37204 KB Output is correct
30 Correct 82 ms 37212 KB Output is correct
31 Correct 49 ms 37708 KB Output is correct
32 Correct 154 ms 40868 KB Output is correct