oj.uz

Submission #631826

# Submission time Handle Problem Language Result Execution time Memory
631826 2022-08-18T21:00:30 Z NintsiChkhaidze One-Way Streets (CEOI17_oneway) C++14
100 / 100
 278 ms 31144 KB 
#include <bits/stdc++.h>
#define s second
#define f first
#define pb push_back
#define left (h<<1),l,((l+r)>>1)
#define right ((h<<1)|1),((l+r)>>1) + 1,r
using namespace std;
 
const int N = 100005;
int tin[N],low[N],a[N],b[N],ID[N],d[25][N];
int O[N],C[N];
bool bridge[N],vis[N];
vector <int> adj[N],vec[N];
vector <pair<int,int> > v[N];
int idx,cnt,n;
 
void dfs(int x,int par){
    vis[x] = 1;
    tin[x] = low[x] = cnt++;
    for (auto [to,id]: v[x]){
        if (to == par) continue;
        if (vis[to]){
            low[x] = min(low[x], tin[to]);
        }else{
            dfs(to,x);
            low[x] = min(low[x], low[to]);
            if (low[to] > tin[x]) bridge[id] = 1;
        }
    }
}
 
void dfs1(int x){
    ID[x] = idx;
    vis[x] = 1;
    for (auto [to,id]: v[x]){
        if (!vis[to] && !bridge[id]) dfs1(to);
        else if (!vis[to] && bridge[id]) vec[idx].pb(to);
    }
}
 
void dfs2(int x,int par){
    vis[x] = 1;
    d[0][x] = par;
    tin[x] = tin[par] + 1;
    for (int to: adj[x])
        if (!vis[to]) dfs2(to,x);
}
 
void dfs3(int x,int par){
    vis[x]=1;
    for (int to: adj[x]) 
        if (to!=par) {
            dfs3(to,x);
            O[x] += O[to];
            C[x] += C[to];
        }
}
int lca(int x,int y){
    if (tin[x] < tin[y]) swap(x,y);
    for (int j = 18; j >= 0; j--)
        if (tin[d[j][x]] >= tin[y]) x = d[j][x];
    if (x == y) return x;
    for (int j = 18; j >=0; j--)
        if(d[j][x] != d[j][y]) x = d[j][x],y = d[j][y];
    return d[0][x];
}
int main (){
    ios_base::sync_with_stdio(0),cin.tie(NULL),cout.tie(NULL);
    int m;
    cin>>n>>m;
    for (int i = 1; i <= m; i++){
        cin>>a[i]>>b[i];
        v[a[i]].pb({b[i],i});
        v[b[i]].pb({a[i],i});
    }
 
    for (int i= 1; i <= n; i++)
        if (!vis[i]) dfs(i,i); 
 
    for (int i = 1; i <= n; i++) {
        sort(v[i].begin(),v[i].end());
        for (int j = 1; j < v[i].size(); j++)
            if (v[i][j].f == v[i][j - 1].f) bridge[v[i][j].s] = bridge[v[i][j - 1].s] = 0;
    }
    
    for (int i= 1; i <= n; i++) 
        vis[i] = 0;

    idx = 0;
    for (int i = 1; i <= n; i++)
        if (!vis[i]) idx++,dfs1(i);
    
    for (int i = 1; i <= n; i++)
        for (int x: vec[i])
            adj[i].pb(ID[x]),adj[ID[x]].pb(i);
            
    for (int i = 1; i <= n; i++)
        tin[i] = 0,vis[i] = 0;
    
    cnt=0;
    for (int i = 1; i <= n; i++) 
        if (!vis[i]) dfs2(i,i);
        
    for (int j = 1; j < 19; j++)
        for (int i = 1; i <= n; i++)
            d[j][i] = d[j - 1][d[j - 1][i]];
 
    int k;
    cin>>k;
    for (int i = 1; i <= k; i++){
        int x,y;
        cin>>x>>y;
        x = ID[x],y = ID[y];
        int c = lca(x,y);
        O[x]++; O[c]--;
        C[y]++; C[c]--;
    }
    
    for (int i = 1; i <= n; i++) vis[i] = 0;
    for (int i = 1; i <= n; i++) if (!vis[i]) dfs3(i,i);
    
    for (int i = 1; i <= m; i++){
        if (!bridge[i]) cout<<'B';
        else{
            int x = ID[a[i]],y = ID[b[i]];
            if (tin[x] >= tin[y]){
                if(O[x] && !C[x]) cout<<'R';
                else if (!O[x] && C[x]) cout<<'L';
                else cout<<'B';
            }else{
                if(O[y] && !C[y]) cout<<'L';
                else if (!O[y] && C[y]) cout<<'R';
                else cout<<'B';
            }
        }
    }
}

Compilation message

oneway.cpp: In function 'void dfs(int, int)':
oneway.cpp:20:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   20 |     for (auto [to,id]: v[x]){
      |               ^
oneway.cpp: In function 'void dfs1(int)':
oneway.cpp:35:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   35 |     for (auto [to,id]: v[x]){
      |               ^
oneway.cpp: In function 'int main()':
oneway.cpp:82:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   82 |         for (int j = 1; j < v[i].size(); j++)
      |                         ~~^~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 7380 KB Output is correct
2 Correct 4 ms 7380 KB Output is correct
3 Correct 4 ms 7508 KB Output is correct
4 Correct 5 ms 7636 KB Output is correct
5 Correct 5 ms 7636 KB Output is correct
6 Correct 5 ms 7508 KB Output is correct
7 Correct 6 ms 7636 KB Output is correct
8 Correct 4 ms 7636 KB Output is correct
9 Correct 6 ms 7508 KB Output is correct
10 Correct 4 ms 7508 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 7380 KB Output is correct
2 Correct 4 ms 7380 KB Output is correct
3 Correct 4 ms 7508 KB Output is correct
4 Correct 5 ms 7636 KB Output is correct
5 Correct 5 ms 7636 KB Output is correct
6 Correct 5 ms 7508 KB Output is correct
7 Correct 6 ms 7636 KB Output is correct
8 Correct 4 ms 7636 KB Output is correct
9 Correct 6 ms 7508 KB Output is correct
10 Correct 4 ms 7508 KB Output is correct
11 Correct 39 ms 13892 KB Output is correct
12 Correct 53 ms 15668 KB Output is correct
13 Correct 59 ms 18276 KB Output is correct
14 Correct 88 ms 22108 KB Output is correct
15 Correct 93 ms 23456 KB Output is correct
16 Correct 84 ms 26820 KB Output is correct
17 Correct 93 ms 28156 KB Output is correct
18 Correct 116 ms 26772 KB Output is correct
19 Correct 108 ms 29316 KB Output is correct
20 Correct 45 ms 16720 KB Output is correct
21 Correct 44 ms 16588 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 7380 KB Output is correct
2 Correct 4 ms 7380 KB Output is correct
3 Correct 4 ms 7508 KB Output is correct
4 Correct 5 ms 7636 KB Output is correct
5 Correct 5 ms 7636 KB Output is correct
6 Correct 5 ms 7508 KB Output is correct
7 Correct 6 ms 7636 KB Output is correct
8 Correct 4 ms 7636 KB Output is correct
9 Correct 6 ms 7508 KB Output is correct
10 Correct 4 ms 7508 KB Output is correct
11 Correct 39 ms 13892 KB Output is correct
12 Correct 53 ms 15668 KB Output is correct
13 Correct 59 ms 18276 KB Output is correct
14 Correct 88 ms 22108 KB Output is correct
15 Correct 93 ms 23456 KB Output is correct
16 Correct 84 ms 26820 KB Output is correct
17 Correct 93 ms 28156 KB Output is correct
18 Correct 116 ms 26772 KB Output is correct
19 Correct 108 ms 29316 KB Output is correct
20 Correct 45 ms 16720 KB Output is correct
21 Correct 44 ms 16588 KB Output is correct
22 Correct 278 ms 28128 KB Output is correct
23 Correct 240 ms 26564 KB Output is correct
24 Correct 216 ms 26816 KB Output is correct
25 Correct 218 ms 31144 KB Output is correct
26 Correct 269 ms 27800 KB Output is correct
27 Correct 220 ms 26924 KB Output is correct
28 Correct 53 ms 10536 KB Output is correct
29 Correct 76 ms 16316 KB Output is correct
30 Correct 76 ms 16472 KB Output is correct
31 Correct 76 ms 17112 KB Output is correct
32 Correct 120 ms 21564 KB Output is correct