Submission #877172

#	Time	Username	Problem	Language	Result	Execution time	Memory
877172		phong	Rigged Roads (NOI19_riggedroads)	C++17	100 / 100	293 ms	70092 KiB

riggedroads

#include<bits/stdc++.h>

#define ll long long
const int nmax = 3e5 + 5;
const ll oo = 1e18;
const int lg = 20;
const int bs = 16785;
const int ts = 16767;
const ll mod = 1e9 + 7;
#define pii pair<int, int>
#define fi first
#define se second
#define debug(a, n) for(int i = 1; i <= n; ++i) cout << a[i] << ' ';
using namespace std;

int n, m, c[nmax];
vector<pii> adj[nmax];
pii a[nmax];
int ans[nmax], h[nmax], up[nmax][lg + 1];
bool vis[nmax], cc[nmax];
int cost[nmax];
int r[nmax];

int get(int u){
    return r[u] ? r[u] = get(r[u]) : u;
}

void dfs(int u, int p, int W){
    cost[u] = W;
    for(auto [w, v] : adj[u]){
        if(v == p) continue;
        h[v] = h[u] + 1;
        up[v][0] = u;
        for(int j = 1; j <= lg; ++j) up[v][j] = up[up[v][j - 1]][j - 1];
        dfs(v, u, w);
    }
}

int lca(int u, int v){
    if(h[u] != h[v]){
        if(h[u] < h[v]) swap(u, v);
        int k = h[u] - h[v];
        for(int j = 0;j <= __lg(k); ++j){
            if(k >> j & 1){
                u = up[u][j];
            }
        }
    }
    if(u == v) return u;
    for(int j = __lg(h[u]); j >= 0; --j){
        if(up[u][j] != up[v][j]){
            u = up[u][j];
            v = up[v][j];
        }
    }
    return up[u][0];
}

int main(){
    ios_base::sync_with_stdio(NULL);
    cin.tie(0);cout.tie(0);
//    freopen("TRAVEL.inp", "r", stdin);
//    freopen("TRAVEL.out", "w", stdout);
    cin >> n >> m;
    for(int i = 1, u, v; i <= m; ++i){
        cin >> u >> v;
        a[i] = {u, v};
    }
    for(int i = 1, x, u, v; i < n; ++i){
        cin >> x;
        u = a[x].fi, v = a[x].se;
        adj[u].push_back({x, v});
        adj[v].push_back({x, u});
        vis[x] = 1;
    }
    dfs(1, -1, 0);
    int cur = 0;
    vector<int> tmp;
    for(int i = 1, u, v; i <= m; ++i){
        u = a[i].fi, v = a[i].se;
        if(h[u] < h[v]) swap(u, v);
        if(ans[i]) continue;
        if(!vis[i]){
            int x = lca(u, v);
            u = get(u); v = get(v);
            while(h[u] > h[x]){
                int it1 = u;
                int it2 = get(up[u][0]);
                r[it1] = it2;
                tmp.push_back(cost[u]);
                u = get(u);
            }
             while(h[v] > h[x]){
                int it1 = v;
                int it2 = get(up[v][0]);
                r[it1] = it2;
                tmp.push_back(cost[v]);
                v = get(v);
            }
            sort(tmp.begin(), tmp.end());
            for(auto id : tmp) ans[id] = ++cur;
            tmp.clear();
            ans[i] = ++cur;
        }
        else{
            ans[i] = ++cur;
            u = get(u), v = get(v);
            r[u] = v;
        }
    }
    for(int i = 1; i <= m; ++i) cout << ans[i] << ' ';
}
/*
4 3 2000
1 2 1050
2 3 1000
2 4 1030
2 1030
1 1020
1 890


*/

• Subtask 1: 8 / 8
• Subtask 2: 19 / 19
• Subtask 3: 9 / 9
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 12 / 12
• Subtask 7: 32 / 32