제출 #441994

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
441994		SorahISA	분수 공원 (IOI21_parks)	C++17	45 / 100	944 ms	58008 KiB

parks

#include "parks.h"
#pragma GCC optimize("Ofast", "unroll-loops")
#include <bits/stdc++.h>
using namespace std;

// #define int long long
// #define double long double
using pii = pair<int, int>;
template<typename T>
using Prior = std::priority_queue<T>;
template<typename T>
using prior = std::priority_queue<T, vector<T>, greater<T>>;

// #define X first
// #define Y second
#define eb emplace_back
#define pb pop_back
#define pf pop_front
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)

namespace {

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

const int maxn = 2E5 + 5;
const int dx[] = {2, 0, -2,  0};
const int dy[] = {0, 2,  0, -2};

map<pii, int> fountain;
vector<int> p(maxn);

vector<int> adj[maxn];

int R(int x) {return x ^ p[x] ? p[x] = R(p[x]) : x;}
int U(int x, int y) {x = R(x), y = R(y); return x ^ y ? p[x] = y, 1 : 0;}

} /// end of namespace

int construct_roads(vector<int> X, vector<int> Y) {
    int N = X.size();
    vector<int> u, v, a, b;
    
    if (N == 1) return build({}, {}, {}, {}), 1;
    
    iota(ALL(p), 0);
    for (int i = 0; i < N; ++i) fountain[{X[i], Y[i]}] = i+1;
    for (int i = 0; i < N; ++i) {
        for (int d = 0; d < 4; ++d) {
            int nei = fountain[{X[i] + dx[d], Y[i] + dy[d]}];
            if (nei-1 > i and U(i, nei-1)) u.eb(i), v.eb(nei-1);
        }
    }
    for (int i = 0; i < N; ++i) if (R(i) != R(0)) return 0;
    
    int M = u.size(); a.assign(M, -1), b.assign(M, -1);
    // assert(M == N-1);
    
    for (int i = 0; i < M; ++i) {
        if (X[u[i]] == X[v[i]]) {
            int midY = Y[u[i]] + Y[v[i]] >> 1;
            if ((X[u[i]] + 1 + midY) % 4 == 2) a[i] = X[u[i]] + 1;
            else a[i] = X[u[i]] - 1;
            b[i] = midY;
        }
    }
    
    for (int i = 0; i < M; ++i) {
        if (Y[u[i]] == Y[v[i]]) {
            int midX = X[u[i]] + X[v[i]] >> 1;
            if ((Y[u[i]] + 1 + midX) % 4 == 0) b[i] = Y[u[i]] + 1;
            else b[i] = Y[u[i]] - 1;
            a[i] = midX;
        }
    }
    
    return build(u, v, a, b), 1;
}

컴파일 시 표준 에러 (stderr) 메시지

parks.cpp: In function 'int construct_roads(std::vector<int>, std::vector<int>)':
parks.cpp:61:32: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   61 |             int midY = Y[u[i]] + Y[v[i]] >> 1;
parks.cpp:70:32: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   70 |             int midX = X[u[i]] + X[v[i]] >> 1;

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