Submission #970326

#	Time	Username	Problem	Language	Result	Execution time	Memory
970326		mychecksedad	Fountain Parks (IOI21_parks)	C++17	30 / 100	873 ms	60760 KiB

parks

#include "parks.h"
#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n';
#define ll long long int
const int N = 3e5+10;

struct Dsu{
    vector<int> s, p;
    Dsu(int n){
        s.resize(n, 1);
        p.resize(n);
        for(int i = 0; i < n; ++i) p[i] = i;
    }
    int find(int v){
        if(p[v] == v) return v;
        return p[v] = find(p[v]);
    }
    void merge(int a, int b){
        a = find(a);
        b = find(b);
        if(a != b){
            if(s[a] > s[b]) swap(a, b);
            p[a] = b;
            s[b] += s[a];
        }
    }
};
int A[4][2] = {{2, 0}, {0, 2}, {-2, 0}, {0, -2}};
        

int construct_roads(std::vector<int> x, std::vector<int> y) {
    if (x.size() == 1) {
    build({}, {}, {}, {});
        return 1;
    }
    int n = x.size();
    vector<int> u, v, a, b;

    Dsu d(n);
    bool other = 0;
    vector<pair<int, int>> L, R, M;
    for(int i = 0; i < n; ++i){
        if(x[i] == 2) L.pb({y[i], i}); 
        else if(x[i] == 6) R.pb({y[i], i});
        else if(x[i] == 4) M.pb({y[i], i});
        else{
            other = 1;
        }
    }
    if(other){
        map<pair<int, int>, int> m;
        map<pair<int, int>, bool> used;
        for(int i = 0; i < n; ++i) m[{x[i], y[i]}] = i + 1;
        for(int i = 0; i < n; ++i){
            for(int j = 0; j < 4; ++j){
                int nx = A[j][0] + x[i], ny = A[j][1] + y[i];
                int val = m[{nx, ny}];
                if(val != 0 && d.find(val - 1) != d.find(i)){
                    d.merge(val - 1, i);
                    u.pb(i);
                    v.pb(val - 1);
                    int fx = A[j][0] == 0 ? x[i] + 1 : x[i] + A[j][0] / 2;
                    int fy = A[j][1] == 0 ? y[i] + 1 : y[i] + A[j][1] / 2;
                    if(used[{fx, fy}]){
                        if(A[j][0] == 0) fx = x[i] - 1;
                        else fy = y[i] - 1;
                    }
                    a.pb(fx);
                    b.pb(fy);
                    used[{fx, fy}] = 1;
                }
            }
        }
    }else{
        sort(all(L));
        sort(all(R));
        sort(all(M));
        for(int i = 0; i + 1 < L.size(); ++i){
            if(L[i].first < L[i + 1].first - 2) continue;
            u.pb(L[i].second);
            v.pb(L[i + 1].second);
            a.pb(1);
            b.pb(L[i + 1].first + L[i].first>>1);
            d.merge(L[i].second, L[i + 1].second);
        }
        for(int i = 0; i + 1 < R.size(); ++i){
            if(R[i].first < R[i + 1].first - 2) continue;
            u.pb(R[i].second);
            v.pb(R[i + 1].second);
            a.pb(7);
            b.pb(R[i + 1].first + R[i].first>>1);
            d.merge(R[i].second, R[i + 1].second);
        }
        for(int i = 0; i + 1 < M.size(); ++i){
            if(M[i].first < M[i + 1].first - 2) continue;
            u.pb(M[i].second);
            v.pb(M[i + 1].second);
            a.pb((M[i].first/2)%2 == 0 ? 5 : 3);
            b.pb(M[i + 1].first + M[i].first>>1);
            d.merge(M[i].second, M[i + 1].second);
        }

        int p = 0, last = -5;
        for(int i = 0; i < M.size(); ++i){
            while(p < R.size() && R[p].first < M[i].first) ++p;
            if(p < R.size() && R[p].first == M[i].first){
                if(last + 2 == M[i].first) continue;
                last = M[i].first;
                u.pb(R[p].second);
                v.pb(M[i].second);
                a.pb(5);
                b.pb(M[i].first + ((M[i].first/2) % 2 == 0 ? -1 : 1));
                d.merge(R[p].second, M[i].second);
            }
        }
        p = 0, last = -5;
        for(int i = 0; i < M.size(); ++i){
            while(p < L.size() && L[p].first < M[i].first) ++p;
            if(p < L.size() && L[p].first == M[i].first){
                if(last + 2 == M[i].first) continue;
                last = M[i].first;
                u.pb(L[p].second);
                v.pb(M[i].second);
                a.pb(3);
                b.pb(M[i].first + ((M[i].first/2) % 2 == 0 ? 1 : -1));
                d.merge(L[p].second, M[i].second);
            }
        }
    }

    if(d.s[d.find(0)] < n) return 0;
    build(u, v, a, b);
    return 1;
}

Compilation message (stderr)

parks.cpp: In function 'int construct_roads(std::vector<int>, std::vector<int>)':
parks.cpp:81:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   81 |         for(int i = 0; i + 1 < L.size(); ++i){
      |                        ~~~~~~^~~~~~~~~~
parks.cpp:86:33: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   86 |             b.pb(L[i + 1].first + L[i].first>>1);
parks.cpp:89:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   89 |         for(int i = 0; i + 1 < R.size(); ++i){
      |                        ~~~~~~^~~~~~~~~~
parks.cpp:94:33: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   94 |             b.pb(R[i + 1].first + R[i].first>>1);
parks.cpp:97:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   97 |         for(int i = 0; i + 1 < M.size(); ++i){
      |                        ~~~~~~^~~~~~~~~~
parks.cpp:102:33: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  102 |             b.pb(M[i + 1].first + M[i].first>>1);
parks.cpp:107:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  107 |         for(int i = 0; i < M.size(); ++i){
      |                        ~~^~~~~~~~~~
parks.cpp:108:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  108 |             while(p < R.size() && R[p].first < M[i].first) ++p;
      |                   ~~^~~~~~~~~~
parks.cpp:109:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |             if(p < R.size() && R[p].first == M[i].first){
      |                ~~^~~~~~~~~~
parks.cpp:120:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  120 |         for(int i = 0; i < M.size(); ++i){
      |                        ~~^~~~~~~~~~
parks.cpp:121:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  121 |             while(p < L.size() && L[p].first < M[i].first) ++p;
      |                   ~~^~~~~~~~~~
parks.cpp:122:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  122 |             if(p < L.size() && L[p].first == M[i].first){
      |                ~~^~~~~~~~~~

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