Submission #400669

#	Time	Username	Problem	Language	Result	Execution time	Memory
400669		teehandsome	Connecting Supertrees (IOI20_supertrees)	C++17	11 / 100	245 ms	26020 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define endl '\n'
#define INF 1e9+7
#define all(x) x.begin(),x.end()
using namespace std;
using namespace __gnu_pbds;
using ll=long long;
using pii=pair<int,int>;
using ppi=pair<int,pii>;
using oset=tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>;

template<typename T>
void _print(vector<T> x) {cerr<<"{"; for(auto e:x) cerr<<e<<","; cerr<<"}";}
void _print(pii x) {cerr<<"{"<<x.first<<","<<x.second<<"}";}
template<typename T>
void _print(T x) {cerr<<x;}

void dbg() {cerr<<endl;}
template<typename Head,typename... Tail>
void dbg(Head H,Tail... T) {
    _print(H);
    if(sizeof...(T)) cerr<<",";
    else cerr<<"\"]";
    dbg(T...);
}
#define debug(...) cerr<<"["<<#__VA_ARGS__<<"]:[\"",dbg(__VA_ARGS__)

const int mxn=1003;
vector<vector<int>> adj,p;
vector<int> group[mxn];
int n;

vector<int> par;
int findp(int x) {
    while(par[x]!=x) par[x]=par[par[x]],x=par[x]; return x;
}
void unionset(int u,int v) {
    int U=findp(u),V=findp(v);
    par[U]=V;
}
bool solve(int root) {
    int sz=group[root].size();
    if(sz==1) return true;
    vector<int> two,one,mix;

    for(int i=0;i<sz;i++) {
        bool isone=false,istwo=false;
        for(int j=0;j<sz;j++) {
            if(j==i) continue;
            if(p[i][j]==0) return false;
            else if(p[i][j]==1) isone=true;
            else if(p[i][j]==2) istwo=true;
        }
        if(isone and !istwo) one.push_back(group[root][i]);
        else if(isone and istwo) mix.push_back(group[root][i]);
        else two.push_back(group[root][i]);
    }
    int l1=one.size();
    int l2=two.size();
    int l12=mix.size();
    if(l1 and (l2 or l12)) return false;
    if(l1) {
        for(int i=0;i<l1-1;i++) {
            int u=one[i];
            int v=one[i+1];
            adj[u][v]=adj[v][u]=1;
        }
        return true;
    }
    if(!l12) {
        for(int i=0;i<l2;i++) {
            int u=two[i];
            int v=two[(i+1)%l2];
            adj[u][v]=adj[v][u]=1;
        }
        return true;
    }
    // !l1 and l2 and l12
    assert(!l1 and l2 and l12);
    for(int i=0;i<l2-1;i++) {
        int u=two[i];
        int v=two[i+1];
        adj[u][v]=adj[v][u]=1;
    }
    for(int i=0;i<l12-1;i++) {
        int u=mix[i];
        int v=mix[i+1];
        adj[u][v]=adj[v][u]=1;
    }
    int u=mix[l12-1];
    adj[u][two[0]]=adj[two[0]][u]=1;
    adj[u][two[l2-1]]=adj[two[l2-1]][u]=1;
//    debug(one);
//    debug(two);
//    debug(mix);
    return true;
}

int construct(std::vector<std::vector<int>> P) {
    p=P;
	n=p.size(); par.resize(n);
	iota(all(par),0);
//	debug(par);
	adj.resize(n,vector<int>(n,0));
	for(int i=0;i<n;i++) {
        for(int j=i+1;j<n;j++) {
            if(p[i][j]!=0) {
                unionset(i,j);
            }
        }
	}
	for(int i=0;i<n;i++) {
        par[i]=findp(par[i]);
	}
	for(int i=0;i<n;i++) {
        for(int j=i+1;j<n;j++) {
            if(p[i][j]>2) return 0;
//            if(!p[i][j]) {
//                if(par[i]==par[j]) return 0;
//            }
//            else {
//                if(par[i]!=par[j]) return 0;
//            }
        }
	}
    for(int i=0;i<n;i++) {
        par[i]=findp(par[i]);
        group[par[i]].push_back(i);
    }
    vector<bool> flag(n+1,false);
    for(int i=0;i<n;i++) {
        if(flag[par[i]]) continue;
        flag[par[i]]=true;
        bool ok=solve(par[i]);
        if(!ok) return 0;
    }
    for(int i=0;i<n;i++) adj[i][i]=0;
    build(adj);
    return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int findp(int)':
supertrees.cpp:38:5: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
   38 |     while(par[x]!=x) par[x]=par[par[x]],x=par[x]; return x;
      |     ^~~~~
supertrees.cpp:38:51: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
   38 |     while(par[x]!=x) par[x]=par[par[x]],x=par[x]; return x;
      |                                                   ^~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 0 / 10
• Subtask 3: 0 / 19
• Subtask 4: 0 / 35
• Subtask 5: 0 / 21
• Subtask 6: 0 / 4