oj.uz

Submission #849149

# Submission time Handle Problem Language Result Execution time Memory
849149 2023-09-14T07:19:13 Z omega One-Way Streets (CEOI17_oneway) C++17
100 / 100
 172 ms 22296 KB 
/* * * * * * * * * * * * * * * * *
 *	author: enmendurana
 *	created: 09-14-2023
 * * * * * * * * * * * * * * * * */

#include <bits/stdc++.h>

using namespace std;

struct buffer : streambuf {
    int overflow(int x) {
        return x;
    }
};

static buffer null_buffer;
static ostream null_stream(&null_buffer);

void local() {
	#if defined(LOCAL_FLAG)
		freopen("/home/omega/Documents/input.in", "r", stdin);
		freopen("/home/omega/Documents/output.out", "w", stdout);
		freopen("/home/omega/Documents/error.err", "w", stderr);
        #define debug cerr
	#else
        #define debug null_stream
	#endif
}

#define ff first
#define ss second
#define pb emplace_back
#define pob pop_back
#define pf emplace_front
#define pof pop_front
#define endl '\n'

typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int uint;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef pair<ll, ll> pll;
typedef tuple<ll,ll,ll> tlll;

const ll mod = ll(1e9 + 7);
const int N = 10'000;
const int maxn = int(1e5)+10;
const int lg = 21;
const double eps = double(1e-9);

/* ALGORITHM */

vector<vector<int>> g;

int edge[maxn], smer[maxn];
int d[maxn], low[maxn], timer = 0;

int p[maxn], cycle[maxn];
int aux[maxn], sz[maxn];

stack<int> st;

int idx[maxn];
int t[4*maxn];

int tarjan_dfs(int prev, int v) {
    d[v] = low[v] = ++timer;
    p[v] = edge[prev] - v;

    sz[v] = 1;
    st.emplace(v);

    for(int i : g[v]) {
        int u = edge[i] - v;
        if(!d[u]) {
            d[u] = d[v] + 1;
            sz[v] += tarjan_dfs(i,u);

            low[v] = min(low[v], low[u]);
        } else if(i != prev) {
            low[v] = min(low[v], d[u]);
        }
    }

    if(d[v] == low[v]) {
        for(int u = 0; u != v;) {
            u = st.top(); st.pop();
            cycle[u] = v;
        }
    }

    return sz[v];
}

void hld(int r, int v) {
    if(aux[v]) return;

    priority_queue<ii> pq;
    aux[v] = r;

    idx[v] = timer++;

    for(int i : g[v]) {
        int u = edge[i] - v;
        if(p[u] == v && u != v) {
            pq.emplace(sz[u], u);
        }
    }

    if(!pq.empty()) {
        auto [w,u] = pq.top(); pq.pop();
        hld(r,u);
    }

    while(!pq.empty()) {
        auto [w,u] = pq.top(); pq.pop();
        hld(u,u);
    }
}

void update(int v, int l, int r, int lx, int rx, int x) {
    if(lx <= l && r <= rx) t[v] = x;
    else if(r <= lx || rx <= l) return;
    else {
        int mid = (l+r)>>1;
        update(2*v,l,mid,lx,rx, x);
        update(2*v+1,mid,r,lx,rx, x);
    }
}

void lca(int v, int u) {
    while(aux[v] != aux[u]) {
        if(d[aux[v]] < d[aux[u]]) {
            update(1,0,2*timer,idx[aux[u]],idx[u]+1,-1);
            u = p[aux[u]];
        } else {
            update(1,0,2*timer,idx[aux[v]],idx[v]+1,1);
            v = p[aux[v]];
        }
    }
    if(d[v] < d[u]) update(1,0,2*timer,idx[v]+1,idx[u]+1,-1);
    if(d[v] > d[u]) update(1,0,2*timer,idx[u]+1,idx[v]+1,1);
}

int mode[maxn];

void build(int v, int l, int r) {
    if(r-l==1) {
        if(l < timer) mode[l] = t[v];
    } else {
        if(t[v] != 0) t[2*v] = t[2*v+1] = t[v];
        int mid = (l+r)>>1;
        build(2*v,l,mid);
        build(2*v+1,mid,r);
    }
}

void solve() {

    int n, m; cin >> n >> m;

    g.resize(n+1);

    for(int v, u, i = 0; i < m; i++) {
        cin >> v >> u; 
        edge[i] = v + u;
        smer[i] = (v < u);
        g[v].pb(i);
        g[u].pb(i);
    }

    for(int v = 1; v <= n; v++) {
        if(!d[v]) {
            edge[m] = 2*v;
            tarjan_dfs(m,v);
        }
    }
    timer = 0;

    for(int v = 1; v <= n; v++) {
        if(v==p[v]) hld(v,v);
    }

    int k; cin >> k;

    for(int v, u; k--;) {
        cin >> v >> u; lca(v,u);
    }

    build(1,0,2*timer);
    string ans; ans.resize(m);

    for(int v = 1; v <= n; v++) {
        for(int i : g[v]) {
            int u = edge[i] - v;
            int op = mode[idx[u]];
            if(cycle[v] == cycle[u]) {
                ans[i] = 'B'; continue;
            }

            if(p[u] == v) {
                if(op==1) {
                    if((u < v) ^ smer[i]) op = -1;
                    else op = 1;
                } else if(op==-1) {
                    if((v < u) ^ smer[i]) op = -1;
                    else op = 1;
                }

                if(op==1) ans[i] = 'R';
                if(op==-1) ans[i] = 'L';
                if(op==0) ans[i] = 'B';
            }
        }
    }

    cout << ans << "\n";
}

signed main() {
	local();
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);

	int t=1; // cin>>t;
	while(t--) {
		solve();
	}

	return 0;
}

// 想上GM捏 想上GM捏 想上GM捏 想上GM捏 想上GM捏
// 伊娜可爱捏 伊娜贴贴捏

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 1 ms 4444 KB Output is correct
4 Correct 1 ms 4444 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 1 ms 4444 KB Output is correct
7 Correct 1 ms 4700 KB Output is correct
8 Correct 1 ms 4444 KB Output is correct
9 Correct 1 ms 4444 KB Output is correct
10 Correct 1 ms 4440 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 1 ms 4444 KB Output is correct
4 Correct 1 ms 4444 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 1 ms 4444 KB Output is correct
7 Correct 1 ms 4700 KB Output is correct
8 Correct 1 ms 4444 KB Output is correct
9 Correct 1 ms 4444 KB Output is correct
10 Correct 1 ms 4440 KB Output is correct
11 Correct 27 ms 10576 KB Output is correct
12 Correct 31 ms 12112 KB Output is correct
13 Correct 39 ms 14164 KB Output is correct
14 Correct 62 ms 15636 KB Output is correct
15 Correct 48 ms 15836 KB Output is correct
16 Correct 37 ms 12836 KB Output is correct
17 Correct 43 ms 15704 KB Output is correct
18 Correct 40 ms 12892 KB Output is correct
19 Correct 52 ms 17744 KB Output is correct
20 Correct 32 ms 12376 KB Output is correct
21 Correct 31 ms 11860 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 1 ms 4444 KB Output is correct
4 Correct 1 ms 4444 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 1 ms 4444 KB Output is correct
7 Correct 1 ms 4700 KB Output is correct
8 Correct 1 ms 4444 KB Output is correct
9 Correct 1 ms 4444 KB Output is correct
10 Correct 1 ms 4440 KB Output is correct
11 Correct 27 ms 10576 KB Output is correct
12 Correct 31 ms 12112 KB Output is correct
13 Correct 39 ms 14164 KB Output is correct
14 Correct 62 ms 15636 KB Output is correct
15 Correct 48 ms 15836 KB Output is correct
16 Correct 37 ms 12836 KB Output is correct
17 Correct 43 ms 15704 KB Output is correct
18 Correct 40 ms 12892 KB Output is correct
19 Correct 52 ms 17744 KB Output is correct
20 Correct 32 ms 12376 KB Output is correct
21 Correct 31 ms 11860 KB Output is correct
22 Correct 133 ms 16916 KB Output is correct
23 Correct 171 ms 14036 KB Output is correct
24 Correct 172 ms 13908 KB Output is correct
25 Correct 114 ms 22296 KB Output is correct
26 Correct 145 ms 16188 KB Output is correct
27 Correct 152 ms 14136 KB Output is correct
28 Correct 29 ms 7760 KB Output is correct
29 Correct 132 ms 12616 KB Output is correct
30 Correct 105 ms 12880 KB Output is correct
31 Correct 99 ms 13496 KB Output is correct
32 Correct 92 ms 17232 KB Output is correct