oj.uz

Submission #118520

# Submission time Handle Problem Language Result Execution time Memory
118520 2019-06-19T07:14:02 Z zubec One-Way Streets (CEOI17_oneway) C++14
100 / 100
 572 ms 25424 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;

const int N = 100100;

vector <pair<int, int > > g[N];

int tin[N], fup[N], tim, tout[N], n, m;

int up[20][N];

bool used[N], isBridge[N];

void dfs(int v, int p){
    used[v] = 1;
    tin[v] = fup[v] = ++tim;
    for (int i = 0; i < g[v].size(); i++){
        int to = g[v][i].first, id = g[v][i].second;
        if (id == p)
            continue;
        if (!used[to]){
            dfs(to, id);
            fup[v] = min(fup[v], fup[to]);
            if (tin[v] < fup[to]){
                isBridge[id] = 1;
            }
        } else {
            fup[v] = min(fup[v], tin[to]);
        }
    }
}

int clr[N], cnt;

void dfs2(int v, int p){
    clr[v] = cnt;
    for (int i = 0; i < g[v].size(); i++){
        int to = g[v][i].first, id = g[v][i].second;
        if (isBridge[id] || clr[to] != 0)
            continue;
        dfs2(to, v);
    }
}

void dfs3(int v, int p){
    tin[v] = ++tim;
    up[0][v] = p;
    for (int i = 1; i < 20; i++){
        up[i][v] = up[i-1][up[i-1][v]];
    }
    for (int i = 0; i < g[v].size(); i++){
        int to = g[v][i].first;
        if (to == p)
            continue;
        dfs3(to, v);
    }
    tout[v] = tim;
}

bool ifpred(int a, int b){
    return tin[a] <= tin[b] && tout[a] >= tout[b];
}

int getlca(int a, int b){
    if (ifpred(a, b))
        return a;
    if (ifpred(b, a))
        return b;
    for (int i = 19; i >= 0; i--){
        int x = up[i][a];
        if (x != 0 && !ifpred(x, b))
            a = x;
    }
    return up[0][a];
}

vector <pair<pair<int, int>, int> > rebr;

int napr[2][N];
int anss[N];

void dfs4(int v, int p, int idpred){
    for (int i = 0; i < g[v].size(); i++){
        int to = g[v][i].first, id = g[v][i].second;
        if (to == p)
            continue;
        dfs4(to, v, id);
        napr[0][v] += napr[0][to];
        napr[1][v] += napr[1][to];
    }
    if (napr[0][v] != 0){
        if (idpred > 0){
            anss[idpred] = 1;
        } else {
            anss[-idpred] = 2;
        }
    }
    if (napr[1][v] != 0){
        if (idpred > 0){
            anss[idpred] = 2;
        } else {
            anss[-idpred] = 1;
        }
    }
}

bool dfs5(int v, int need, int p){
    if (v == need)
        return 1;
    for (int i = 0; i < g[v].size(); i++){
        int to = g[v][i].first, id = g[v][i].second;
        if (to == p)
            continue;
        if (dfs5(to, need, v)){
            if (id > 0){
                anss[id] = 2;
            } else {
                anss[-id] = 1;
            }
            return 1;
        }
    }
    return 0;
}

int main(){
    ios_base::sync_with_stdio(0);cin.tie(0);

    cin >> n >> m;
    for (int i = 1; i <= m; i++){
        int u, v;
        cin >> u >> v;
        rebr.push_back({{u, v}, i});
        g[u].push_back({v, i});
        g[v].push_back({u, i});
    }
    for (int i = 1; i <= n; i++){
        if (!used[i])
            dfs(i, 0);
    }
    for (int i = 1; i <= n; i++){
        if (clr[i] == 0){
            ++cnt;
            dfs2(i, 0);
        }
    }
    for (int i = 1; i <= n; i++){
        g[i].clear();
    }
    for (int i = 0; i < rebr.size(); i++){
        int u = rebr[i].first.first, v = rebr[i].first.second, id = rebr[i].second;
        if (clr[u] != clr[v]){
            g[clr[u]].push_back({clr[v], id});
            g[clr[v]].push_back({clr[u], -id});
        }
    }
    //n = cnt;
    tim = 0;
    dfs3(1, 0);

    int tt;
    cin >> tt;
    int ttt = tt;
    while(tt--){
        int a, b;
        cin >> a >> b;
        if (clr[a] != clr[b]){
            a = clr[a];
            b = clr[b];
            int lca = getlca(a, b);
            ++napr[0][a];
            ++napr[1][b];
            --napr[0][lca];
            --napr[1][lca];
            //cout << "kek " << a << ' ' << b << endl;
            if (ttt <= 100)
            dfs5(a, b, 0);
        }
    }
    if (ttt > 1000)
    dfs4(1, 0, 0);
    for (int i = 1; i <= m; i++){
        if (anss[i] == 0)
            cout << 'B'; else
        if (anss[i] == 1)
            cout << 'L'; else
            cout << 'R';
    }

}

/**

5 6
1 2
1 2
4 3
2 3
1 3
5 1
2
4 5
1 3

*/

Compilation message

oneway.cpp: In function 'void dfs(int, int)':
oneway.cpp:19:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < g[v].size(); i++){
                     ~~^~~~~~~~~~~~~
oneway.cpp: In function 'void dfs2(int, int)':
oneway.cpp:39:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < g[v].size(); i++){
                     ~~^~~~~~~~~~~~~
oneway.cpp: In function 'void dfs3(int, int)':
oneway.cpp:53:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < g[v].size(); i++){
                     ~~^~~~~~~~~~~~~
oneway.cpp: In function 'void dfs4(int, int, int)':
oneway.cpp:85:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < g[v].size(); i++){
                     ~~^~~~~~~~~~~~~
oneway.cpp: In function 'bool dfs5(int, int, int)':
oneway.cpp:112:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < g[v].size(); i++){
                     ~~^~~~~~~~~~~~~
oneway.cpp: In function 'int main()':
oneway.cpp:152:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < rebr.size(); i++){
                     ~~^~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 2816 KB Output is correct
2 Correct 3 ms 2816 KB Output is correct
3 Correct 4 ms 2944 KB Output is correct
4 Correct 5 ms 2944 KB Output is correct
5 Correct 5 ms 2944 KB Output is correct
6 Correct 5 ms 3072 KB Output is correct
7 Correct 5 ms 3072 KB Output is correct
8 Correct 5 ms 2944 KB Output is correct
9 Correct 5 ms 2944 KB Output is correct
10 Correct 5 ms 2944 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 2816 KB Output is correct
2 Correct 3 ms 2816 KB Output is correct
3 Correct 4 ms 2944 KB Output is correct
4 Correct 5 ms 2944 KB Output is correct
5 Correct 5 ms 2944 KB Output is correct
6 Correct 5 ms 3072 KB Output is correct
7 Correct 5 ms 3072 KB Output is correct
8 Correct 5 ms 2944 KB Output is correct
9 Correct 5 ms 2944 KB Output is correct
10 Correct 5 ms 2944 KB Output is correct
11 Correct 55 ms 9132 KB Output is correct
12 Correct 56 ms 10000 KB Output is correct
13 Correct 81 ms 11532 KB Output is correct
14 Correct 118 ms 14632 KB Output is correct
15 Correct 111 ms 15696 KB Output is correct
16 Correct 146 ms 18624 KB Output is correct
17 Correct 344 ms 21544 KB Output is correct
18 Correct 291 ms 19388 KB Output is correct
19 Correct 572 ms 21876 KB Output is correct
20 Correct 66 ms 9640 KB Output is correct
21 Correct 60 ms 10004 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 2816 KB Output is correct
2 Correct 3 ms 2816 KB Output is correct
3 Correct 4 ms 2944 KB Output is correct
4 Correct 5 ms 2944 KB Output is correct
5 Correct 5 ms 2944 KB Output is correct
6 Correct 5 ms 3072 KB Output is correct
7 Correct 5 ms 3072 KB Output is correct
8 Correct 5 ms 2944 KB Output is correct
9 Correct 5 ms 2944 KB Output is correct
10 Correct 5 ms 2944 KB Output is correct
11 Correct 55 ms 9132 KB Output is correct
12 Correct 56 ms 10000 KB Output is correct
13 Correct 81 ms 11532 KB Output is correct
14 Correct 118 ms 14632 KB Output is correct
15 Correct 111 ms 15696 KB Output is correct
16 Correct 146 ms 18624 KB Output is correct
17 Correct 344 ms 21544 KB Output is correct
18 Correct 291 ms 19388 KB Output is correct
19 Correct 572 ms 21876 KB Output is correct
20 Correct 66 ms 9640 KB Output is correct
21 Correct 60 ms 10004 KB Output is correct
22 Correct 220 ms 22288 KB Output is correct
23 Correct 187 ms 20648 KB Output is correct
24 Correct 216 ms 20832 KB Output is correct
25 Correct 256 ms 25424 KB Output is correct
26 Correct 246 ms 21928 KB Output is correct
27 Correct 232 ms 20904 KB Output is correct
28 Correct 38 ms 7212 KB Output is correct
29 Correct 75 ms 10512 KB Output is correct
30 Correct 83 ms 10920 KB Output is correct
31 Correct 81 ms 10796 KB Output is correct
32 Correct 117 ms 15660 KB Output is correct