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Submission #1027477

# Submission time Handle Problem Language Result Execution time Memory
1027477 2024-07-19T06:51:50 Z vjudge1 One-Way Streets (CEOI17_oneway) C++17
100 / 100
 75 ms 22724 KB 
#include <bits/stdc++.h>
#define ll int
#define ull unsigned long long
#define ld long double
#define pb push_back
#define pf push_front
#define vi vector<ll>
#define vii vector<vi>
#define pll pair<ll, ll>
#define vpll vector<pll>
#define all(a) a.begin(), a.end()
#define fi first
#define se second
using namespace std;
const ll mod = 1e9 + 7;
const ll inf = 2e18;
const ll blocksz = 320;
const ll N = 1e5 + 8;
ll num[N],low[N],tdfs,m,n,q;
bool vst[N];
vpll adj[N];
bool bridge[N];
vpll edge = {{0,0}};
void dfs_bridge(ll u, ll p){
    num[u] = low[u] = ++tdfs;
    for(pll ed:adj[u]){
        ll v = ed.fi, id = ed.se;
        if(v == p) continue;
        if(!num[v]){
            dfs_bridge(v,u);
            low[u] = min(low[u],low[v]);
            if(low[v] == num[v]){
                bridge[id] = 1;
            }
        }
        else low[u] = min(low[u],num[v]);
    }
}
ll cc[N],cntcc;
void dfs_component(ll u){
    cc[u] = cntcc;
    vst[u] = 1;
    for(pll ed:adj[u]){
        ll v = ed.fi, id = ed.se;
        if(bridge[id]) continue;
        if(vst[v]) continue;
        dfs_component(v);
    }
}
struct node{
    ll v,id,x,y;
};
vector<node> g[N];
void build(){
    for(ll i = 1; i <= n; i++) if(!num[i]) tdfs = 0, dfs_bridge(i,i);
    for(ll i = 1; i <= n; i++) if(!vst[i]) cntcc++,dfs_component(i);
    for(ll i = 1; i <= m; i++){
        ll u = edge[i].fi, v = edge[i].se;
        if(bridge[i]){
            g[cc[u]].pb({cc[v],i,u,v});
            g[cc[v]].pb({cc[u],i,v,u});
        }
    }
}
ll dp[N];
pll ans[N];
void direct(ll u, ll p){
    vst[u] = 1;
    for(node v:g[u]){
        if(v.v == p || vst[v.v]) continue;
        v.x = u, v.y = v.v;
        direct(v.v,u);
    }
}
void dfs(ll u, ll p) {
    vst[u] = 1;
    for(node v:g[u]){
        if(v.v == p || vst[v.v]) continue;
        dfs(v.v, u);
        dp[u] += dp[v.v];
        if(dp[v.v] > 0) ans[v.id] = {v.y, v.x};
        if(dp[v.v] < 0) ans[v.id] = {v.x, v.y};
    }
}
void solve(){
    cin >> n >> m;
    for(ll i = 1; i <= m; i++){
        ans[i] = {-1,-1};
        ll u,v;cin >> u >> v;
        adj[u].pb({v,i});
        adj[v].pb({u,i});
        edge.pb({u,v});
    }
    build();
    fill(vst,vst+n+1,0);
    for(ll i = 1; i <= n; i++) if(!vst[i]) direct(i,i); 
    cin >> q;
    while(q--){
        ll u,v;cin >> u >> v;
        dp[cc[u]]++;
        dp[cc[v]]--;
    }
    fill(vst,vst+n+1,0);
    for(ll i = 1; i <= n; i++) if(!vst[i]) dfs(i,i);
    for(ll i = 1; i <= m; i++) {
        if(ans[i].fi < 0 || !bridge[i]) cout << "B";
        else cout << (ans[i] == edge[i] ? "R" : "L");
    }
}
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen("test.inp", "r")){
        freopen("test.inp", "r", stdin);
        freopen("test.out", "w", stdout);
    }
    ll T = 1;
    // cin >> T;
    for (ll i = 1; i <= T; i++){
        solve();
        cout << '\n';
    }
}

Compilation message

oneway.cpp:16:16: warning: overflow in conversion from 'double' to 'int' changes value from '2.0e+18' to '2147483647' [-Woverflow]
   16 | const ll inf = 2e18;
      |                ^~~~
oneway.cpp: In function 'int main()':
oneway.cpp:115:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  115 |         freopen("test.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
oneway.cpp:116:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  116 |         freopen("test.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6488 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 1 ms 6748 KB Output is correct
4 Correct 2 ms 6744 KB Output is correct
5 Correct 2 ms 6748 KB Output is correct
6 Correct 1 ms 6748 KB Output is correct
7 Correct 1 ms 6748 KB Output is correct
8 Correct 1 ms 6748 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 1 ms 6492 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6488 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 1 ms 6748 KB Output is correct
4 Correct 2 ms 6744 KB Output is correct
5 Correct 2 ms 6748 KB Output is correct
6 Correct 1 ms 6748 KB Output is correct
7 Correct 1 ms 6748 KB Output is correct
8 Correct 1 ms 6748 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 1 ms 6492 KB Output is correct
11 Correct 24 ms 11736 KB Output is correct
12 Correct 29 ms 12492 KB Output is correct
13 Correct 32 ms 13516 KB Output is correct
14 Correct 37 ms 14888 KB Output is correct
15 Correct 48 ms 15476 KB Output is correct
16 Correct 56 ms 17348 KB Output is correct
17 Correct 40 ms 19012 KB Output is correct
18 Correct 42 ms 17348 KB Output is correct
19 Correct 41 ms 20420 KB Output is correct
20 Correct 26 ms 12160 KB Output is correct
21 Correct 25 ms 11976 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6488 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 1 ms 6748 KB Output is correct
4 Correct 2 ms 6744 KB Output is correct
5 Correct 2 ms 6748 KB Output is correct
6 Correct 1 ms 6748 KB Output is correct
7 Correct 1 ms 6748 KB Output is correct
8 Correct 1 ms 6748 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 1 ms 6492 KB Output is correct
11 Correct 24 ms 11736 KB Output is correct
12 Correct 29 ms 12492 KB Output is correct
13 Correct 32 ms 13516 KB Output is correct
14 Correct 37 ms 14888 KB Output is correct
15 Correct 48 ms 15476 KB Output is correct
16 Correct 56 ms 17348 KB Output is correct
17 Correct 40 ms 19012 KB Output is correct
18 Correct 42 ms 17348 KB Output is correct
19 Correct 41 ms 20420 KB Output is correct
20 Correct 26 ms 12160 KB Output is correct
21 Correct 25 ms 11976 KB Output is correct
22 Correct 51 ms 19144 KB Output is correct
23 Correct 53 ms 17352 KB Output is correct
24 Correct 66 ms 17204 KB Output is correct
25 Correct 55 ms 22724 KB Output is correct
26 Correct 65 ms 18680 KB Output is correct
27 Correct 75 ms 17348 KB Output is correct
28 Correct 20 ms 9680 KB Output is correct
29 Correct 35 ms 11728 KB Output is correct
30 Correct 33 ms 11728 KB Output is correct
31 Correct 36 ms 12096 KB Output is correct
32 Correct 40 ms 15824 KB Output is correct