Submission #803252

#	Time	Username	Problem	Language	Result	Execution time	Memory
803252		vjudge1	Fountain Parks (IOI21_parks)	C++17	15 / 100	120 ms	27420 KiB

parks

#include "parks.h"
#include<bits/stdc++.h>
using namespace std;
bitset<200100> have[8];
int at[8][200100];
int construct1(int row) {
    vector<int>u,v,x,y;
    int prev = 0;
    for(int i = 2; i <= 200000; i+=2) {
        if(have[row][i]) {
            if(prev) {
                if(i-prev>2)
                    return 0;
                u.push_back(at[row][i]);
                v.push_back(at[row][i-2]);
                x.push_back(row+1);
                y.push_back(i-1);
            }
            prev = i;
        }
    }
    build(u,v,x,y);
    return 1;
}
int p[200100];
int abp(int n) {
    if(p[n]==n) return n;
    return p[n]=abp(p[n]);
}
int n;
int construct2(int row1, int row2) {
    int prev1 = 0, prev2 = 0;
    vector<pair<pair<int, int>, pair<int, int>>> edges;
    for(int i = 2; i <= 200000; i+=2) {
        if(have[row2][i]&&i>2){
            if(have[row2][i-2])
                edges.push_back({{at[row2][i], at[row2][i-2]}, {row2+1, i-1}});
        }
        if(have[row1][i]) {
            if(i>2) {
                if(have[row1][i-2])
                    edges.push_back({{at[row1][i], at[row1][i-2]}, {row1-1, i-1}});
            }
            if(have[row2][i])
                edges.push_back({{at[row1][i], at[row2][i]}, {row1+1, i-1}});
        }
    }
    iota(p,p+200100,0);
    vector<int> u,v,x,y;
    for(auto i: edges)
        u.push_back(i.first.first), v.push_back(i.first.second),x.push_back(i.second.first),y.push_back(i.second.second);
    int cnt = 0;
    for(int i = 0; i < edges.size(); i++)
        if(abp(u[i])!=abp(v[i]))
            p[p[u[i]]]=p[v[i]],cnt++;
    if(cnt!=n-1) return 0;
    build(u,v,x,y);
    return 1;
}
int construct_roads(vector<int> x, vector<int> y) {
    n = x.size();
    for(int i = 0; i < n; i++)
        have[x[i]][y[i]] = 1,at[x[i]][y[i]]=i;
    int a = have[2].count(), b = have[4].count(), c = have[6].count();
    if(!a&&!b) return construct1(6);
    if(!a&&!c) return construct1(4);
    if(!c&&!b) return construct1(2);
    if(!b) return 0;
    if(!c) return construct2(2,4);
    if(!a) return construct2(4,6);
    vector<pair<pair<int, int>, pair<int, int>>> edges,edges2;
    bool app=1;
    for(int i = 2; i <= 200000; i+=2) {
        if(have[6][i]&&have[6][i-2])
            edges.push_back({{at[6][i-2],at[6][i]}, {7,i-1}});
        if(have[4][i]){
            if(have[6][i]&&have[2][i]) app=0;
            if(have[6][i])
                edges.push_back({{at[4][i], at[6][i]}, {5, i+(app?1:-1)}}),app=1;
            if(have[4][i-2])
                edges2.push_back({{at[4][i], at[4][i-2]}, {3, i-1}});
        }
        if(have[2][i]) {
            if(have[2][i-2])
                edges.push_back({{at[2][i], at[2][i-2]}, {1, i-1}});
            if(have[4][i])
                edges.push_back({{at[2][i], at[4][i]}, {3, i+(app?1:-1)}}),app=1;
        }
    }
    for(auto i: edges2)
        edges.push_back(i);
    iota(p,p+200100,0);
    vector<int> u,v,X,Y;
    int cnt = 0;
    for(int i = 0; i < edges.size(); i++)
        if(abp(edges[i].first.first)!=abp(edges[i].first.second)){
            p[p[edges[i].first.first]]=p[edges[i].first.second],cnt++,
            u.push_back(edges[i].first.first), v.push_back(edges[i].first.second),
            X.push_back(edges[i].second.first), Y.push_back(edges[i].second.second);
            if(have[X.back()][Y.back()]) {
                X.back()+=2;
            }
            have[X.back()][Y.back()]=1;
        }
    if(u.size()!=n-1) return 0;
    build(u,v,X,Y);
    return 1;
}

Compilation message (stderr)

parks.cpp: In function 'int construct2(int, int)':
parks.cpp:53:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<std::pair<int, int>, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |     for(int i = 0; i < edges.size(); i++)
      |                    ~~^~~~~~~~~~~~~~
parks.cpp:32:9: warning: unused variable 'prev1' [-Wunused-variable]
   32 |     int prev1 = 0, prev2 = 0;
      |         ^~~~~
parks.cpp:32:20: warning: unused variable 'prev2' [-Wunused-variable]
   32 |     int prev1 = 0, prev2 = 0;
      |                    ^~~~~
parks.cpp: In function 'int construct_roads(std::vector<int>, std::vector<int>)':
parks.cpp:95:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<std::pair<int, int>, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   95 |     for(int i = 0; i < edges.size(); i++)
      |                    ~~^~~~~~~~~~~~~~
parks.cpp:105:16: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  105 |     if(u.size()!=n-1) return 0;
      |        ~~~~~~~~^~~~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30