Submission #1118847

#	Time	Username	Problem	Language	Result	Execution time	Memory
1118847		yusufhocaoglu	Swapping Cities (APIO20_swap)	C++17	36 / 100	281 ms	52920 KiB

swap

#include "swap.h"

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define MOD2 998244353
#define ll long long
#define pri pair<int,int>
#define prl pair<ll,ll>
#define vi vector<int>
#define vl vector<ll>
#define vp vector<pair<int,int>>
#define vpl vector<pair<ll,ll>>
#define re return 0
#define sqrt sqrtl

vi dsu;
vi parent;
vi cnt;
vi sz;
vi weight;
vector<vi> adj;

void make_set(int x) {
    dsu[x] = x;
    parent[x] = x;
    sz[x] = 1;
    cnt[x] = 0;
    weight[x] = 0;
}

int get_root(int u) {
    if (dsu[u]==u) return u;
    return dsu[u] = get_root(dsu[u]);
}
int s;
vp edges;
void unite(int u,int v,int w) {
    edges[s] = {u,v};
    u = get_root(u);
    v = get_root(v);
    //cout<<"uniting "<<u<<" and "<<v<<" to "<<s<<endl;
    make_set(s);

    dsu[u] = dsu[v] = s;
    parent[u] = parent[v] = s;
    adj[s].push_back(u);
    weight[s] = w;
    if (u==v) sz[s]+=sz[u], cnt[s]+=cnt[u];
    else {
        sz[s]+=sz[u]+sz[v];
        cnt[s]+=cnt[u]+cnt[v];
        adj[s].push_back(v);
    }

    s++;
}

void tour(int u) {
    cout<<u<<" "<<weight[u]<<endl;
    for (auto m : adj[u]) {
        //cout<<"niggas gonna from "<<u<<" to "<<m<<endl;
        tour(m);
    }
}

vector<vi> adj_mst;

vi stf;
vp chain;

void dfs(int u) {
    if (chain[u].first==-1) stf[u] = u;
    else if (parent[u]!=u) stf[u] = stf[parent[u]];
    else stf[u] = -1;
    for (auto m : adj[u]) {
        dfs(m);
    }
}


pri cc(pri a,pri b,pri c) {
    //chain,chain,edge
    if (a.first == c.first && b.first == c.second) {
        return {a.second,b.second};
    } 
    if (a.second == c.first && b.first == c.second) {
        return {a.first,b.second};
    } 
    if (a.first == c.first && b.second == c.second) {
        return {a.second,b.first};
    } 
    if (a.second == c.first && b.second == c.second) {
        return {a.first,b.first};
    } 
    return {-1,-1};
}

vp ln2;
vp lnf;
vp seg2;
void dfs2(int u,int h) { // on the reachability tree
    lnf[u].first = ln2.size();
    ln2.push_back({h,u});
    for (auto v : adj[u]) {
        dfs2(v,h+1);
        ln2.push_back({h,u});
    }
    if (adj[u].size()==0) chain[u] = {u,u};
    else if (adj[u].size()==1) chain[u] = {-1,-1};
    else if (chain[adj[u][0]].first==-1 || chain[adj[u][1]].first==-1) chain[u]={-1,-1};
    else {
        //each child forms a chain
        //edge is edges[u].first - edges[u].second
        auto uc = chain[adj[u][0]];
        auto vc = chain[adj[u][1]];

        chain[u] = cc(uc,vc,edges[u]);

    }
    lnf[u].second = ln2.size()-1;
}

int lca2(int u,int v) {
    int l = min(lnf[u].first,lnf[v].first);
    int r = max(lnf[u].second,lnf[v].second);
    l+=ln2.size();
    r+=ln2.size();
    r++;
    pri ans = {1e9,1e9};
    for (;l<r;l>>=1,r>>=1) {
        if (l&1) {
            ans = min(ans,seg2[l++]);
        } if (r&1) {
            ans = min(ans,seg2[--r]);
        }
    }
    return ans.second;

}

int getMinimumFuelCapacity(int u,int v) {
    //pri lca1_ = lca(u,v);
    int lca2_ = lca2(u,v);
    //int path_len = node_l[fl[u].first].first+node_l[fl[v].first].first - lca1_.second*2; 
    if (chain[lca2_].first==-1) {
        return weight[lca2_];
    } else {
        //find earliest parent with no chain
        if (stf[lca2_]==-1) return -1;
        else return weight[stf[lca2_]];
    }
}

void init(int n,int m,vector<int> u,vector<int> v,vector<int> w) {
    dsu = vi(2*n+1);
    parent = vi(2*n+1);
    sz = vi(2*n+1);
    cnt = vi(2*n+1);
    adj = vector<vi>(2*n+1);
    weight = vi(2*n+1);

    s = n;

    struct edge {
        int u,v,w;
        bool operator<(const edge& other) const {
            return w<other.w;
        }
    };
    for (int i = 0;i<n;i++){
        make_set(i);
        cnt[i] = 1;
    }
    //cout<<"nigga"<<endl;
    vector<edge> ss;
    vector<edge> edging;
    for (int i = 0;i<m;i++) ss.push_back(edge{u[i],v[i],w[i]});
    sort(ss.begin(),ss.end());
    adj_mst = vector<vi>(n);
    edges = vp(2*n+1);
    for (auto edge : ss) {
        if (get_root(edge.u)!=get_root(edge.v)) {
            adj_mst[edge.u].push_back(edge.v);
            adj_mst[edge.v].push_back(edge.u);
        }
        unite(edge.u,edge.v,edge.w);
    }
    
    //cout<<cnt[s-1]<<endl;
    
    lnf = vp(2*n+1);
    chain = vp(2*n+1);
    dfs2(s-1,0);
    seg2 = vp(2*ln2.size()+2);
    for (int i = 0;i<ln2.size();i++) {
        seg2[i+ln2.size()] = ln2[i];
    }
    for (int i = ln2.size()-1;i>0;i--) {
        seg2[i] = min(seg2[2*i],seg2[2*i+1]);
    }
    stf = vi(2*n+1);
    dfs(s-1);
}

/*int32_t main() {
    int u[6] = {0,0,1,1,1,2};
    int v[6] = {1,2,2,3,4,3};
    int w[6] = {4,4,1,2,10,3};
    init(5, 6, u, v,w);
    cout<<getMinimumFuelCapacity(1,2)<<endl;
    return 0;
}*/

Compilation message (stderr)

swap.cpp: In function 'void init(int, int, std::vector<int>, std::vector<int>, std::vector<int>)':
swap.cpp:197:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  197 |     for (int i = 0;i<ln2.size();i++) {
      |                    ~^~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 0 / 17
• Subtask 4: 0 / 20
• Subtask 5: 23 / 23
• Subtask 6: 0 / 27