oj.uz

Submission #986270

# Submission time Handle Problem Language Result Execution time Memory
986270 2024-05-20T07:42:14 Z Do_you_copy One-Way Streets (CEOI17_oneway) C++17
100 / 100
 90 ms 39108 KB 
    #include <bits/stdc++.h>
    //#define int long long
    #define fi first
    #define se second
    #define pb push_back
    #define faster ios_base::sync_with_stdio(0); cin.tie(0);
    using namespace std;
    using ll = long long;
    using ull = unsigned ll;
    using ld = long double;
    using pii = pair <int, int>;
    using pil = pair <int, ll>;
    using pli = pair <ll, int>;
    using pll = pair <ll, ll>;
    mt19937 Rand(chrono::steady_clock::now().time_since_epoch().count());
     
    ll min(const ll &a, const ll &b){
        return (a < b) ? a : b;
    }
     
    ll max(const ll &a, const ll &b){
        return (a > b) ? a : b;
    }
     
    //const ll Mod = 1000000007;
    //const ll Mod2 = 999999999989;
    //only use when required
    const int maxN = 2e5 + 1;
    int n, m, k;
     
    struct TDSU{
        vector <pii> save;
        vector <int> lab;
        TDSU(){}
        TDSU(int _n){
            lab.resize(_n, -1);
        }
        inline void resize(int _n){
            lab.resize(_n, -1);
        }
        inline int find_set(int u){
            if (lab[u] < 0) return u;
            return lab[u] = find_set(lab[u]);
        }
        inline int find(int u){
            if (lab[u] < 0) return u;
            return find(lab[u]);
        }
        inline void merge(int u, int v){
            if (lab[u] > lab[v]) swap(u, v);
            save.pb({v, lab[v]});
            lab[u] += lab[v];
            lab[v] = u;
        }
        inline void undo(){
     
            int v = save.back().fi;
            int u = lab[v];
            lab[v] = save.back().se;
            lab[u] -= lab[v];
            save.pop_back();
        }
        inline void clear(){
            lab.clear();
            save.clear();
        }
        inline void reset(int _n){
            clear();
            resize(_n);
        }
        inline void roll_back(int _n){
            while (save.size() > _n) undo();
        }
    };
    TDSU dsu;
    int timedfs, low[maxN], num[maxN];
    int id[maxN];
    int mark[maxN];
    int node_cnt;
     
    struct TEdge{
        int u, v, idx;
    };
    TEdge e[maxN];
    vector <TEdge> adj[maxN];
     
    void dfs(int u, int idx){
        low[u] = num[u] = ++timedfs;
        for (auto i: adj[u]){
            int v = i.u ^ i.v ^ u;
            if (i.idx == idx) continue;
            if (!num[v]){
                dfs(v, i.idx);
                low[u] = min(low[u], low[v]);
                if (low[v] == num[v]) mark[i.idx] = 1;
            }
            else{
                low[u] = min(low[u], num[v]);
            }
        }
    }
     
    vector <pii> adj1[maxN];
    int lift[maxN][20];
    int depth[maxN];
    int val[maxN];
     
    void dfs1(int u, int p){
        lift[u][0] = p;
        depth[u] = depth[p] + 1;
        for (int i = 1; i < 20; ++i){
            lift[u][i] = lift[lift[u][i - 1]][i - 1];
            if (!lift[u][i]) break;
        }
        for (auto i: adj1[u]){
            int v = i.fi;
            if (v == p) continue;
            dfs1(v, u);
        }
    }
     
    int lca(int u, int v){
        if (depth[u] < depth[v]) swap(u, v);
        int k = depth[u] - depth[v];
        while (k){
            int t = k & -k;
            u = lift[u][__lg(t)];
            k -= t;
        }
        if (u == v) return u;
        for (int i = 19; i >= 0; --i){
            if (lift[u][i] != lift[v][i]){
                u = lift[u][i];
                v = lift[v][i];
            }
        }
        return lift[u][0];
    }
     
    void dfs2(int u, int p){
        for (auto i: adj1[u]){
            int v = i.fi;
            if (v == p) continue;
            dfs2(v, u);
            val[u] += val[v];
        }
    }
     
    void Init(){
        cin >> n >> m;
        for (int i = 1; i <= m; ++i){
            cin >> e[i].u >> e[i].v;
            e[i].idx = i;
            adj[e[i].u].pb(e[i]);
            adj[e[i].v].pb(e[i]);
        }
        for (int i = 1; i <= n; ++i){
            if (!num[i]) dfs(i, 0);
        }
        dsu.resize(n + 1);
        vector <int> bridge;
        for (int i = 1; i <= m; ++i){
            if (!mark[i]){
                int x = dsu.find_set(e[i].u);
                int y = dsu.find_set(e[i].v);
                if (x != y){
                    dsu.merge(x, y);
                }
            }
            else bridge.pb(i);
        }
        for (int i = 1; i <= n; ++i){
            int j = dsu.find_set(i);
            if (!id[j]) id[j] = ++node_cnt;
            id[i] = id[j];
        }
        for (int i: bridge){
            int u = id[e[i].u];
            int v = id[e[i].v];
            adj1[u].pb({v, i});
            adj1[v].pb({u, -i});
        }
        for (int i = 1; i <= node_cnt; ++i){
            if (!lift[i][0]){
                dfs1(i, 0);
            }
        }
        cin >> k;
        for (int i = 1; i <= k; ++i){
            int u, v;
            cin >> u >> v;
            u = id[u];
            v = id[v];
            ++val[u];
            --val[v];
        }
        for (int i = 1; i <= node_cnt; ++i){
            if (!lift[i][0]){
                dfs2(i, 0);
            }
        }
        for (int i = 1; i <= m; ++i){
            int x = id[e[i].u];
            int y = id[e[i].v];
            if (x == y) cout << "B";
            if(depth[x]>depth[y]){
                if(!val[x]) cout<<"B";
                if(val[x] > 0) cout<<"R";
                if(val[x] < 0) cout<<"L";
            }
            if(depth[x] < depth[y]){
                if(!val[y]) cout<<"B";
                if(val[y] > 0) cout<<"L";
                if(val[y] < 0) cout<<"R";
            }
        }
    }
     
    #define debu
    #define taskname "test"
    signed main(){
        if (fopen(taskname".inp", "r")){
            freopen(taskname".inp", "r", stdin);
            #ifdef debug
            freopen(taskname".out", "w", stdout);
            #endif
        }
        faster;
        ll tt = 1;
        //cin >> tt;
        while (tt--){
            Init();
        }
        if (fopen("timeout.txt", "r")){
            ofstream timeout("timeout.txt");
            timeout << 1000 * double(clock()) / CLOCKS_PER_SEC;
            #ifndef debug
            cerr << "\nTime elapsed: " << 1000 * double(clock()) / CLOCKS_PER_SEC << "ms\n";
            #endif
        }
    }

Compilation message

oneway.cpp: In member function 'void TDSU::roll_back(int)':
oneway.cpp:72:32: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   72 |             while (save.size() > _n) undo();
      |                    ~~~~~~~~~~~~^~~~
oneway.cpp: In function 'int main()':
oneway.cpp:223:20: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  223 |             freopen(taskname".inp", "r", stdin);
      |             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 10584 KB Output is correct
2 Correct 2 ms 10588 KB Output is correct
3 Correct 3 ms 10844 KB Output is correct
4 Correct 3 ms 10844 KB Output is correct
5 Correct 3 ms 10844 KB Output is correct
6 Correct 3 ms 10844 KB Output is correct
7 Correct 3 ms 10844 KB Output is correct
8 Correct 3 ms 10844 KB Output is correct
9 Correct 2 ms 10588 KB Output is correct
10 Correct 3 ms 10588 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 10584 KB Output is correct
2 Correct 2 ms 10588 KB Output is correct
3 Correct 3 ms 10844 KB Output is correct
4 Correct 3 ms 10844 KB Output is correct
5 Correct 3 ms 10844 KB Output is correct
6 Correct 3 ms 10844 KB Output is correct
7 Correct 3 ms 10844 KB Output is correct
8 Correct 3 ms 10844 KB Output is correct
9 Correct 2 ms 10588 KB Output is correct
10 Correct 3 ms 10588 KB Output is correct
11 Correct 30 ms 19648 KB Output is correct
12 Correct 33 ms 20980 KB Output is correct
13 Correct 37 ms 22484 KB Output is correct
14 Correct 43 ms 26124 KB Output is correct
15 Correct 50 ms 28688 KB Output is correct
16 Correct 63 ms 34000 KB Output is correct
17 Correct 72 ms 35280 KB Output is correct
18 Correct 65 ms 33904 KB Output is correct
19 Correct 67 ms 36304 KB Output is correct
20 Correct 34 ms 20180 KB Output is correct
21 Correct 31 ms 20176 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 10584 KB Output is correct
2 Correct 2 ms 10588 KB Output is correct
3 Correct 3 ms 10844 KB Output is correct
4 Correct 3 ms 10844 KB Output is correct
5 Correct 3 ms 10844 KB Output is correct
6 Correct 3 ms 10844 KB Output is correct
7 Correct 3 ms 10844 KB Output is correct
8 Correct 3 ms 10844 KB Output is correct
9 Correct 2 ms 10588 KB Output is correct
10 Correct 3 ms 10588 KB Output is correct
11 Correct 30 ms 19648 KB Output is correct
12 Correct 33 ms 20980 KB Output is correct
13 Correct 37 ms 22484 KB Output is correct
14 Correct 43 ms 26124 KB Output is correct
15 Correct 50 ms 28688 KB Output is correct
16 Correct 63 ms 34000 KB Output is correct
17 Correct 72 ms 35280 KB Output is correct
18 Correct 65 ms 33904 KB Output is correct
19 Correct 67 ms 36304 KB Output is correct
20 Correct 34 ms 20180 KB Output is correct
21 Correct 31 ms 20176 KB Output is correct
22 Correct 90 ms 36308 KB Output is correct
23 Correct 86 ms 34760 KB Output is correct
24 Correct 87 ms 35020 KB Output is correct
25 Correct 82 ms 39108 KB Output is correct
26 Correct 82 ms 36040 KB Output is correct
27 Correct 79 ms 34916 KB Output is correct
28 Correct 24 ms 16984 KB Output is correct
29 Correct 44 ms 20944 KB Output is correct
30 Correct 43 ms 21200 KB Output is correct
31 Correct 53 ms 21724 KB Output is correct
32 Correct 54 ms 27084 KB Output is correct