oj.uz

Submission #152720

# Submission time Handle Problem Language Result Execution time Memory
152720 2019-09-09T09:36:04 Z Mercenary One-Way Streets (CEOI17_oneway) C++14
100 / 100
 297 ms 23260 KB 
#include<bits/stdc++.h>

using namespace std;
#define taskname "A"
#define pb	push_back
#define mp 	make_pair
#ifndef LOCAL
#define cerr if(0)cout
#endif

typedef long double ld;
typedef long long ll;
typedef pair<int,int> ii;
const int maxn = 1e5 + 5;

int n, m , p;

struct edge{
    int used , u , v , col;
}e[maxn];

vector<int> adj[maxn];
int num[maxn] , low[maxn];
static int nTime = 0 , nGroup = 0;

void DFS(int u){
    low[u] = num[u] = ++nTime;
    for(int c : adj[u]){
        if(e[c].used)continue;
        e[c].used = 1;
        int v = e[c].u + e[c].v - u;
        if(num[v] == 0){
            DFS(v);
            low[u] = min(low[u] , low[v]);
        }else{
            low[u] = min(low[u] , num[v]);
        }
    }
    for(int c : adj[u]){
        int v = e[c].u + e[c].v - u;
//        cout << u << " " << v << " " << c << " " << low[v] << " " << num[v] << endl;
        if(num[u] < num[v] && low[v] == num[v])e[c].col = -1;
    }
}

void DFS1(int u){
    num[u] = nGroup;
    for(int c : adj[u]){
        if(num[e[c].u + e[c].v - u] == 0 && e[c].col != -1){
            DFS1(e[c].u + e[c].v - u);
        }
    }
}

int par[maxn];
int path[maxn];

const int logn = 17;
int P[maxn][logn] , h[maxn];

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if(fopen(taskname".INP","r")){
		freopen(taskname".INP", "r",stdin);
		freopen(taskname".OUT", "w",stdout);
    }
    cin >> n >> m;
    for(int i = 1 ; i <= m ; ++i){
        cin >> e[i].u >> e[i].v;
        adj[e[i].u].pb(i);
        adj[e[i].v].pb(i);
    }
    for(int i = 1 ; i <= n ; ++i){
        if(num[i] == 0)DFS(i);
    }
    fill_n(num,maxn,0);
    for(int i = 1 ; i <= n ; ++i){
        if(num[i] == 0){
            ++nGroup;
            DFS1(i);
        }
    }
    for(int i = 1 ; i <= n ; ++i){
        adj[i].clear();
    }
    for(int i = 1 ; i <= m ; ++i){
        e[i].u = num[e[i].u];
        e[i].v = num[e[i].v];
        if(e[i].col == -1){
            adj[e[i].u].pb(i);
            adj[e[i].v].pb(i);
        }
    }
    function<void(int)> DFS = [&](int u){
        low[u] = 1;
        for(int c : adj[u]){
            int v = e[c].u + e[c].v - u;
            if(low[v] == 1)continue;
            par[v] = c;
            path[v] = u;
            h[v] = h[u] + 1;
            P[v][0] = u;
            for(int i = 1 ; i < logn ; ++i){
                P[v][i] = P[P[v][i - 1]][i - 1];
            }
            DFS(v);
        }
    };
    fill_n(low,maxn,0);
    for(int i = 1 ; i <= nGroup ; ++i){
        if(low[i] == 0){
            DFS(i);
        }
    }
//    for(int i = 1 ; i <= nGroup ; ++i){
//        cout << i << " " << P[i][0] << endl;
//    }
    cin >> p;
    for(int i = 1 ; i <= p ; ++i){
        int u , v;cin >> u >> v;
        u = num[u];v = num[v];
        auto FindLCA = [&](int u , int v){
            if(h[u] < h[v])swap(u , v);
            for(int i = 0 ; i < logn ; ++i){
                if(((h[u] - h[v]) >> i) & 1){
                    u = P[u][i];
                }
            }
            if(u == v)return u;
            for(int i = logn - 1 ; i >= 0 ; --i){
                if(P[u][i] != P[v][i]){
                    u = P[u][i];
                    v = P[v][i];
                }
            }
            return P[u][0];
        };
        function<int(int)> FindPath = [&](int u){
                if(u == 0)return 0;
                if(e[par[path[u]]].col == -1)return path[u];
                return path[u] = FindPath(path[u]);
            };
        auto Travel = [&](int u , int v , int delta){
            while(h[u] > h[v]){
                int c = par[u];
//                if(e[c].col != -1)cout << c << endl;
                int pre = e[c].col;
                if(e[c].u == P[e[c].v][0]){
                    e[c].col = delta;
                }else{
                    e[c].col = 3 - delta;
                }
                u = FindPath(u);
            }
        };
        int c = FindLCA(u , v);
//        for(int j = 1 ; j <= nGroup ; ++j)cout << FindPath(j) << " ";cout << endl;
        Travel(u , c , 1);
        Travel(v , c , 2);
    }
    for(int i = 1 ; i <= m ; ++i){
        if(e[i].col <= 0)cout << "B";
        else if(e[i].col == 2)cout << "R";
        else cout << "L";
    }
}

Compilation message

oneway.cpp: In lambda function:
oneway.cpp:148:21: warning: unused variable 'pre' [-Wunused-variable]
                 int pre = e[c].col;
                     ^~~
oneway.cpp: In function 'int main()':
oneway.cpp:65:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen(taskname".INP", "r",stdin);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
oneway.cpp:66:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen(taskname".OUT", "w",stdout);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 3448 KB Output is correct
2 Correct 5 ms 3576 KB Output is correct
3 Correct 5 ms 3576 KB Output is correct
4 Correct 6 ms 3704 KB Output is correct
5 Correct 6 ms 3704 KB Output is correct
6 Correct 5 ms 3576 KB Output is correct
7 Correct 6 ms 3704 KB Output is correct
8 Correct 6 ms 3704 KB Output is correct
9 Correct 5 ms 3576 KB Output is correct
10 Correct 5 ms 3576 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 3448 KB Output is correct
2 Correct 5 ms 3576 KB Output is correct
3 Correct 5 ms 3576 KB Output is correct
4 Correct 6 ms 3704 KB Output is correct
5 Correct 6 ms 3704 KB Output is correct
6 Correct 5 ms 3576 KB Output is correct
7 Correct 6 ms 3704 KB Output is correct
8 Correct 6 ms 3704 KB Output is correct
9 Correct 5 ms 3576 KB Output is correct
10 Correct 5 ms 3576 KB Output is correct
11 Correct 58 ms 8952 KB Output is correct
12 Correct 65 ms 9848 KB Output is correct
13 Correct 101 ms 11100 KB Output is correct
14 Correct 91 ms 13432 KB Output is correct
15 Correct 94 ms 14456 KB Output is correct
16 Correct 117 ms 17400 KB Output is correct
17 Correct 119 ms 18936 KB Output is correct
18 Correct 139 ms 17400 KB Output is correct
19 Correct 128 ms 20088 KB Output is correct
20 Correct 69 ms 9464 KB Output is correct
21 Correct 59 ms 9208 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 3448 KB Output is correct
2 Correct 5 ms 3576 KB Output is correct
3 Correct 5 ms 3576 KB Output is correct
4 Correct 6 ms 3704 KB Output is correct
5 Correct 6 ms 3704 KB Output is correct
6 Correct 5 ms 3576 KB Output is correct
7 Correct 6 ms 3704 KB Output is correct
8 Correct 6 ms 3704 KB Output is correct
9 Correct 5 ms 3576 KB Output is correct
10 Correct 5 ms 3576 KB Output is correct
11 Correct 58 ms 8952 KB Output is correct
12 Correct 65 ms 9848 KB Output is correct
13 Correct 101 ms 11100 KB Output is correct
14 Correct 91 ms 13432 KB Output is correct
15 Correct 94 ms 14456 KB Output is correct
16 Correct 117 ms 17400 KB Output is correct
17 Correct 119 ms 18936 KB Output is correct
18 Correct 139 ms 17400 KB Output is correct
19 Correct 128 ms 20088 KB Output is correct
20 Correct 69 ms 9464 KB Output is correct
21 Correct 59 ms 9208 KB Output is correct
22 Correct 242 ms 20156 KB Output is correct
23 Correct 233 ms 18552 KB Output is correct
24 Correct 254 ms 18544 KB Output is correct
25 Correct 297 ms 23260 KB Output is correct
26 Correct 224 ms 19824 KB Output is correct
27 Correct 247 ms 18704 KB Output is correct
28 Correct 56 ms 7288 KB Output is correct
29 Correct 97 ms 10232 KB Output is correct
30 Correct 96 ms 10360 KB Output is correct
31 Correct 96 ms 10832 KB Output is correct
32 Correct 146 ms 14968 KB Output is correct