Submission #570929

#	Time	Username	Problem	Language	Result	Execution time	Memory
570929		bojackduy	One-Way Streets (CEOI17_oneway)	C++11	0 / 100	6 ms	5332 KiB

oneway

#include<bits/stdc++.h>
#define int long long
#define task "task"
#define size() size() * 1ll 
#define all(x) (x).begin(), (x).end()
#define allr(x, sz) (x) + 1, (x) + 1 + sz
#define pb push_back
#define pii pair<int,int>
#define fi first
#define se second
#define MASK(x) (1LL<<(x))
#define BIT(x,i) (((x)>>(i))&1)
#define numbit(x) __builtin_popcountll(x)
 
using namespace std;
 
const int N = 1e5 + 1;
const int M = 1e3 + 1;
const long long mod = 1e9 + 7;
const long long oo = 1e18 + 7;
 
typedef vector<int> vi;
typedef vector<pii> vii;
typedef long long ll;
 
template<class t>
bool mini(t &x,t y) {
    if (x > y) {
       x = y;
       return 1;
    }
return 0;
}
template<class t>
bool maxi(t &x,t y) {
    if (x < y) {
       x = y;
       return 1;
    }
return 0;
}
void file() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    // freopen(task".in", "r", stdin);
    // freopen(task".out", "w", stdout);
return ;
}
 
int n, m, p;
pii e[N];
vi a[N], adj[N];
map<pii, int> mp, mp1;
 
stack<int> st;
int num[N], low[N];
 
void dfs(int u, int chu) {
    st.push(u);
    num[u] = low[u] = ++num[0];
    for (auto v: a[u]) if (v != chu) {
        if (num[v]) mini(low[u], num[v]); else {
            dfs(v, u);
            mini(low[u], low[v]);
        }
    }
 
    if (num[u] == low[u]) {
        int v;
        low[0]++;
        do {
            v = st.top(), st.pop();
            num[v] = low[v] = mod + low[0];
        } while (v != u);
    }
}
 
 
int cha[N];
void dfs1(int u, int chu) {
    cha[u] = chu;
    num[u] = 1;
    for (auto v: adj[u]) if (!num[v] && v != chu) {
        dfs1(v, u);
    }
}
 
 
int dp[N];
void dfs2(int u, int chu) {
    num[u] = 0;
    for (auto v: adj[u]) if (num[v] && v != chu) {
        dfs2(v, u);
        dp[u] += dp[v];
    }
}
 
void solve(int test = -1) {
    cin >> n >> m;
    for (int i = 1; i <= m; i++) {
        int x, y;
        cin >> x >> y;
        a[x].pb(y);
        a[y].pb(x);
        e[i] = pii(x, y);
    }
 
    for (int i = 1; i <= n; i++) if (!num[i])
        dfs(i, 0);
    for (int i = 1; i <= n; i++) {
        num[i] = 0;
        for (auto v: a[i]) {
            if (low[i] != low[v]) {
                adj[low[i] - mod].pb(low[v] - mod);
            }
        }
    }
    for (int i = 1; i <= low[0]; i++) if (!num[i])
        dfs1(i, 0);
    
    cin >> p;
    for (int i = 1; i <= p; i++) {
        int x, y;
        cin >> x >> y;
        x = low[x] - mod;
        y = low[y] - mod;
        dp[x]++;
        dp[y]--;
    }

    for (int i = 1; i <= low[0]; i++) if (num[i])
        dfs2(i, 0);


    for (int i = 2; i <= low[0]; i++) {
        int u = cha[i];
        mp[pii(i, u)] = dp[i];
        mp[pii(u, i)] = -dp[i];
    }
 
    for (int i = 1; i <= n; i++) {
        for (auto v: a[i]) {
            mp1[pii(i, v)] = mp[pii(low[i] - mod, low[v] - mod)];
        }
    }
 
    for (int i = 1; i <= m; i++) {
        int u = e[i].fi;
        int v = e[i].se;
        if (mp1[pii(u, v)] == 0) cout << "B"; else {
            if (mp1[pii(u, v)] > 0) cout << "R"; else cout << "L";
        } 
    }
}
 
int32_t main()  {
    file();
    int T = 1;
    // cin >> T;
    for (int i = 1; i <= T; i++) {
        solve(i);
    }
return 0;
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40