제출 #1010247

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1010247		ByeWorld	One-Way Streets (CEOI17_oneway)	C++14	100 / 100	184 ms	77140 KiB

oneway

#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
#define ll long long
#define int long long
#define pb push_back
#define fi first
#define se second
#define lf (id<<1)
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
#define ld long double
using namespace std;
typedef pair<int,int> pii;
typedef pair<pii, int> ipii;
const int MAXN = 3e5+10;
const int MAXA = 2e3+10;
const int INF = 1e18+10;
const int LOG = 19;
const int MOD = 1e9+7;
const int SQRT = 450;
const vector<int> NOL = {};
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const vector<int> dx = {1, -1, 0, 0};
const vector<int> dy = {0, 0, 1, -1};

int n, m, q;
int u[MAXN], v[MAXN];
vector <pii> adj[MAXN];
int tim, disc[MAXN], low[MAXN], col[MAXN];
int up[MAXN], dw[MAXN], br[MAXN];
int ty[MAXN];

void dfs(int nw, int idxpar){
    disc[nw] = low[nw] = ++tim;
    for(auto [nx, idx] : adj[nw]){
        if(idx == idxpar) continue;
        if(disc[nx] == -1){
            dfs(nx, idx); 
            if(disc[nx] == low[nx]){
                br[idx] = 1; // bridge
            }
            low[nw] = min(low[nw], low[nx]);
        } else low[nw] = min(low[nw], disc[nx]); // udh pernah vis

    }
}
void color(int nw, int COL){
    col[nw] = COL;
    for(auto [nx, idx] : adj[nw]){
        if(col[nx]!=-1 || br[idx]) continue;
        color(nx, COL);
    }
}
vector <pii> edge[MAXN];
int anc[MAXN][LOG+5], dep[MAXN];
void trav(int nw, int par){
    disc[nw] = 1;
    anc[nw][0] = par; dep[nw] = dep[par]+1;
    for(auto [nx, idx] : edge[nw]){
        if(nx==par) continue;
        trav(nx, nw);
    }
}

int LCA(int x, int y){
    if(dep[x] > dep[y]) swap(x, y);
    for(int i=LOG-1; i>=0; i--){
        if(dep[anc[y][i]] >= dep[x]){
            y = anc[y][i];
        }
    }
    if(x==y) return x;
    for(int i=LOG-1; i>=0; i--){
        if(anc[y][i] != anc[x][i]){
            y = anc[y][i]; x = anc[x][i];
        }
    }
    return anc[x][0];
}

int idxedge[MAXN];
void bd(int nw){
    // cout << nw << " nw\n";
    disc[nw] = 1;
    for(auto [nx, idx] : edge[nw]){ // nw->nx = idx
        if(disc[nx]==1) continue;
        bd(nx);
        idxedge[nx] = idx;
        up[nw] += up[nx]; dw[nw] += dw[nx];
    }
}
signed main(){
    // ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    cin >> n >> m;
    for(int i=1; i<=m; i++){
        cin >> u[i] >> v[i];
        adj[u[i]].pb({v[i], i}); adj[v[i]].pb({u[i], i});
    }
    // 1. detect bridge
    memset(disc, -1, sizeof disc);
    for(int i=1; i<=n; i++){
        if(disc[i] == -1) dfs(i, 0);
    }
    // 2. bridge tree
    int cnt = 0; memset(col, -1, sizeof col);
    for(int i=1; i<=n; i++){
        if(col[i] == -1) color(i, ++cnt);
    }
    for(int i=1; i<=m; i++){
        if(col[u[i]] == col[v[i]]) continue;
        edge[col[u[i]]].pb({col[v[i]], i});
        edge[col[v[i]]].pb({col[u[i]], -i});
    }
    // for(int i=1; i<=n; i++){
    //     cout << i << ' ' << col[i] << " pp\n";
    // }
    // for(int i=1; i<=m; i++){
    //     if(br[i]) cout << u[i] << ' ' << v[i] << " bri\n";
    // }
    // LCA
    memset(disc, -1, sizeof disc);
    for(int i=1; i<=n; i++){
        if(disc[i]==-1) trav(i, 0);
    }
    // cout << "pp\n";
    for(int j=1; j<LOG; j++)
        for(int i=1; i<=n; i++)
            anc[i][j] = anc[ anc[i][j-1] ][j-1];
    
    cin >> q;
    while(q--){
        int x, y; cin >> x >> y;
        x = col[x]; y = col[y];
        int lca = LCA(x, y);
        up[x]++; up[lca]--;
        dw[y]++; dw[lca]--; 
        // cout << lca << " lca\n";
        // cout << x << ' ' << dep[x] << " up\n";
        // cout << y << ' ' << dep[y] << " dw\n";
    }
    // for(int i=1; i<=3; i++){
    //     cout << i << ' ' << up[i] << ' ' << dw[i] << "pre\n";
    // }
    memset(disc, -1, sizeof disc);
    for(int i=1; i<=cnt; i++){
        if(disc[i] == -1){
            // cout << i << " ii\n"; 
            bd(i);
        }
    }
    for(int i=1; i<=n; i++){ // node di bridge tree
        // cout << i << ' ' << idxedge[i] << " pp\n";
        if(up[i]!=0 && dw[i]!=0) continue;
        int id = idxedge[i];
        // cout << i << ' ' <<up[i] << ' ' << dw[i] << " updw\n";
        if(up[i]!=0){ // nx->nw
            if(id < 0) ty[-id] = -1;
            else ty[id] = 1;
        }

        if(dw[i]!=0){ // nw->nx
            if(id < 0) ty[-id] = 1;
            else ty[id] = -1;
        }
    }

    // OUTPUT
    for(int i=1; i<=m; i++){
        if(ty[i]==1) cout << 'L';
        else if(ty[i]==-1) cout << 'R';
        else cout << 'B';
    }
    cout << '\n';
}

컴파일 시 표준 에러 (stderr) 메시지

oneway.cpp: In function 'void dfs(long long int, long long int)':
oneway.cpp:35:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   35 |     for(auto [nx, idx] : adj[nw]){
      |              ^
oneway.cpp: In function 'void color(long long int, long long int)':
oneway.cpp:49:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   49 |     for(auto [nx, idx] : adj[nw]){
      |              ^
oneway.cpp: In function 'void trav(long long int, long long int)':
oneway.cpp:59:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   59 |     for(auto [nx, idx] : edge[nw]){
      |              ^
oneway.cpp: In function 'void bd(long long int)':
oneway.cpp:85:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   85 |     for(auto [nx, idx] : edge[nw]){ // nw->nx = idx
      |              ^

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