Submission #886093

#	Time	Username	Problem	Language	Result	Execution time	Memory
886093		Kutan	One-Way Streets (CEOI17_oneway)	C++14	0 / 100	2 ms	10844 KiB

oneway

// Cao Quang Hung
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>

using namespace std;
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define pii pair<int,int>
#define pll pair<long long , long long>
#define vi vector<int>
#define vpii vector<pii>
#define SZ(x) ((int)(x.size()))
#define fi first
#define se second
#define IN(x,y) ((y).find((x))!=(y).end())
#define ALL(t) t.begin(),t.end()
#define FOREACH(i,t) for (typeof(t.begin()) i=t.begin(); i!=t.end(); i++)
#define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
#define REPD(i,a,b) for(int (i)=(a); (i)>=(b);--i)
#define FOR(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define dem(x) __builtin_popcount(x)
#define Mask(x) (1LL << (x))
#define BIT(x, i) ((x) >> (i) & 1)
#define ln '\n'
#define io_faster ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
///mt19937 rnd(time(0));

const int INF = 1e9 , mod = 1e9 + 7;

template <class T1, class T2>
inline T1 mul(T1& x, const T2 &k){ return x = (1LL * x * k) % mod; }

template <class T1 , class T2>
inline T1 pw(T1 x, T2 k){T1 res = 1; for (; k ; k >>= 1){ if (k & 1) mul(res, x); mul(x, x); } return res;}

template <class T>
inline bool minimize(T &x, const T &y){ if (x > y){x = y; return 1;} return 0; }

template <class T>
inline bool maximize(T &x, const T &y){ if (x < y){x = y; return 1;} return 0; }

template <class T>
inline void add(T &x , const T &y){ if ((x += y) >= mod) x -= mod; }

template <class T>
inline T product (const T &x , const T &y) { return 1LL * x * y % mod; }

#define PROB "a"
void file(){
    if(fopen(PROB".inp", "r")){
        freopen(PROB".inp","r",stdin);
        freopen(PROB".out","w",stdout);
    }
}
void sinh_(){
//    srand(time(0));
//    freopen(PROB".inp" , "w" , stdout);
//    int n;
}

typedef long long ll;
typedef double db;
const int N = 1e5 + 5;

int n, m, q;
pii edge[N], ans[N];
vi adj[N];
vpii g[N];

bool used[N];
int num[N], low[N], timeDfs = 0;
int numScc = 0, comp[N];
int par[N][17], depth[N], edge_id[N];
bool oke[N];
vi scc[N];

int other(int x, int id) {
    return x ^ edge[id].fi ^ edge[id].se;
}

void readip(){
    cin >> n >> m;
    REP(i, 1, m) {
        int u, v; cin >> u >> v;
        adj[u].eb(i);
        adj[v].eb(i);
        edge[i] = {u, v};
    }
}

vector<int> st;
void dfs(int u) {
    st.eb(u);
    num[u] = low[u] = ++timeDfs;
    for (const auto &id : adj[u]) if (!used[id]) {
        int v = other(u, id);
        used[id] = true;
        if (num[v]) minimize(low[u], num[v]);
        else {
            dfs(v);
            minimize(low[u], low[v]);
        }
    }
    if (num[u] == low[u]) {
        ++numScc;
        int x;
        do {
            x = st.back();
            st.pop_back();
            comp[x] = numScc;
            scc[numScc].eb(x);
        } while(x != u);
    }
}

void dfs_tree(int u, int p) {
    for (const auto &[v, id] : g[u]) if (v != p) {
        edge_id[v] = id;
        depth[v] = depth[u] + 1;
        par[v][0] = u;
        REP(i, 1, 16) par[v][i] = par[par[v][i - 1]][i - 1];
        dfs_tree(v, u);
    }
}

int Lca(int u, int v) {
    if (depth[u] > depth[v]) swap(u, v);
    int dif = depth[v] - depth[u];
    REP(i, 0, 16) if (BIT(dif, i)) v = par[v][i];
    if (u == v) return u;
    REPD(i, 16, 0) if (par[v][i] != par[u][i])
        u = par[u][i] , v = par[v][i];
    return par[u][0];
}

struct query{
    int u, v;
    query(int _u = 0, int _v = 0) {
        u = _u, v = _v;
    }
    bool operator < (const query &other) const {
        return depth[Lca(u, v)] < depth[Lca(other.u, other.v)];
    }
} Query[N];

#define UP 1
#define DOWN 2

void direct(int u, int anc, int d) {
    while(u != anc) {
        int Par = par[u][0];
        int nid = edge_id[u];
        
        if (oke[nid]) return;
        oke[nid] = true;

        ans[nid] = edge[nid];
        if (d == UP) {
            // u -> Par
            if (comp[ans[nid].first] != u)
                swap(ans[nid].first, ans[nid].second);
        }
        else {
            // Par -> u;
            if (comp[ans[nid].first] != Par)
                swap(ans[nid].first, ans[nid].second);
        }
        u = Par;
    }
} 

void solve(){           
    dfs(1); 
    REP(i, 1, numScc) {
        for (int u : scc[i]) for (int id : adj[u]) {
            int v = other(u, id);
            if (comp[v] == i) continue;
            g[i].eb(comp[v], id);
        }
    }   
    dfs_tree(1, -1);
    cin >> q;
    REP(i, 1, q) {
        cin >> Query[i].u >> Query[i].v;
        Query[i].u = comp[Query[i].u];
        Query[i].v = comp[Query[i].v];
    }
    sort(Query + 1, Query + q + 1);
    REP(i, 1, q) {
        int lca = Lca(Query[i].u, Query[i].v);
        direct(Query[i].u, lca, UP);
        direct(Query[i].v, lca, DOWN);
    }

    REP(i, 1, m) {
        if (comp[edge[i].fi] == comp[edge[i].se]) cout << "B";
        else if (edge[i] == ans[i]) cout << "R";
        else cout << "L";
    }
}   

int main(){
    sinh_();
    io_faster
    file();
    int t = 1;
//    cin >> t;
    while (t--){
        readip();
        solve();
    }
}

Compilation message (stderr)

oneway.cpp: In function 'void readip()':
oneway.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
oneway.cpp:157:5: note: in expansion of macro 'REP'
  157 |     REP(i, 1, m) {
      |     ^~~
oneway.cpp: In function 'void dfs_tree(int, int)':
oneway.cpp:191:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  191 |     for (const auto &[v, id] : g[u]) if (v != p) {
      |                      ^
oneway.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
oneway.cpp:195:9: note: in expansion of macro 'REP'
  195 |         REP(i, 1, 16) par[v][i] = par[par[v][i - 1]][i - 1];
      |         ^~~
oneway.cpp: In function 'int Lca(int, int)':
oneway.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
oneway.cpp:203:5: note: in expansion of macro 'REP'
  203 |     REP(i, 0, 16) if (BIT(dif, i)) v = par[v][i];
      |     ^~~
oneway.cpp:93:29: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   93 | #define REPD(i,a,b) for(int (i)=(a); (i)>=(b);--i)
      |                             ^
oneway.cpp:205:5: note: in expansion of macro 'REPD'
  205 |     REPD(i, 16, 0) if (par[v][i] != par[u][i])
      |     ^~~~
oneway.cpp: In function 'void solve()':
oneway.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
oneway.cpp:248:5: note: in expansion of macro 'REP'
  248 |     REP(i, 1, numScc) {
      |     ^~~
oneway.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
oneway.cpp:257:5: note: in expansion of macro 'REP'
  257 |     REP(i, 1, q) {
      |     ^~~
oneway.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
oneway.cpp:263:5: note: in expansion of macro 'REP'
  263 |     REP(i, 1, q) {
      |     ^~~
oneway.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
oneway.cpp:269:5: note: in expansion of macro 'REP'
  269 |     REP(i, 1, m) {
      |     ^~~
oneway.cpp: In function 'void file()':
oneway.cpp:125:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  125 |         freopen(PROB".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
oneway.cpp:126:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  126 |         freopen(PROB".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40