/*
Mayoeba Yabureru
*/
#include<bits/stdc++.h>
using namespace std;
static vector<int> _u, _v, _a, _b;
int construct_roads(vector<int> x, vector<int> y) {
int n = x.size();
vector<vector<int>> gr(n + 1);
x.insert(x.begin(), 0);
y.insert(y.begin(), 0);
map<pair<int, int>, int> mp;
for (int i = 1; i <= n; i ++) mp[{x[i], y[i]}] = i;
vector<int> u, v, a, b;
map<pair<pair<int, int>, pair<int, int>>, int> connected;
map<pair<int, int>, int> taken;
for (int i = 1; i <= n; i ++) {
if (x[i] == 2 && mp[{x[i], y[i] + 2}]) {
connected[{{x[i], y[i]}, {x[i], y[i] + 2}}] = 1;
u.push_back(i), v.push_back(mp[{x[i], y[i] + 2}]);
a.push_back(x[i] - 1), b.push_back(y[i] + 1);
taken[{x[i] - 1, y[i] + 1}] = 1;
gr[i].push_back(mp[{x[i], y[i] + 2}]);
gr[mp[{x[i], y[i] + 2}]].push_back(i);
}
else if (x[i] == 6 && mp[{x[i], y[i] + 2}]) {
connected[{{x[i], y[i]}, {x[i], y[i] + 2}}] = 1;
u.push_back(i), v.push_back(mp[{x[i], y[i] + 2}]);
a.push_back(x[i] + 1), b.push_back(y[i] + 1);
taken[{x[i] + 1, y[i] + 1}] = 1;
gr[i].push_back(mp[{x[i], y[i] + 2}]);
gr[mp[{x[i], y[i] + 2}]].push_back(i);
}
else if (x[i] == 4 && mp[{x[i], y[i] + 2}]) {
connected[{{x[i], y[i]}, {x[i], y[i] + 2}}] = 1;
u.push_back(i), v.push_back(mp[{x[i], y[i] + 2}]);
if (y[i] % 4 == 2) a.push_back(x[i] + 1);
else a.push_back(x[i] - 1);
b.push_back(y[i] + 1);
taken[{a.back(), b.back()}] = 1;
gr[i].push_back(mp[{x[i], y[i] + 2}]);
gr[mp[{x[i], y[i] + 2}]].push_back(i);
}
}
for (int i = 1; i <= n; i ++) {
if (x[i] == 2 && mp[{x[i] + 2, y[i]}]) {
if (connected[{{x[i], y[i] - 2}, {x[i] + 2, y[i] - 2}}] == 1) continue;
u.push_back(i), v.push_back(mp[{x[i] + 2, y[i]}]);
if (taken[{x[i] + 1, y[i] + 1}] == 0) a.push_back(x[i] + 1), b.push_back(y[i] + 1);
else if (taken[{x[i] + 1, y[i] - 1}] == 0) a.push_back(x[i] + 1), b.push_back(y[i] - 1);
else assert(0);
gr[i].push_back(mp[{x[i] + 2, y[i]}]);
gr[mp[{x[i] + 2, y[i]}]].push_back(i);
}
else if (x[i] == 6 && mp[{x[i] - 2, y[i]}]) {
if (connected[{{x[i], y[i] - 2}, {x[i] - 2, y[i] - 2}}] == 1) continue;
u.push_back(i), v.push_back(mp[{x[i] - 2, y[i]}]);
if (taken[{x[i] - 1, y[i] + 1}] == 0) a.push_back(x[i] - 1), b.push_back(y[i] + 1);
else if (taken[{x[i] - 1, y[i] - 1}] == 0) a.push_back(x[i] - 1), b.push_back(y[i] - 1);
else assert(0);
gr[i].push_back(mp[{x[i] - 2, y[i]}]);
gr[mp[{x[i] - 2, y[i]}]].push_back(i);
}
}
for (int i = 0; i < u.size(); i ++) {
u[i] --;
v[i] --;
}
int num = 0;
vector<int> vis(n + 1);
function<void(int)> go = [&] (int x) {
num ++;
vis[x] = 1;
for (auto u : gr[x]) {
if (vis[u]) continue;
go(u);
}
};
go(1);
if (num == n) {
build(u, v, a, b);
return 1;
}
}
Compilation message
parks.cpp: In function 'int construct_roads(std::vector<int>, std::vector<int>)':
parks.cpp:71:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
71 | for (int i = 0; i < u.size(); i ++) {
| ~~^~~~~~~~~~
parks.cpp:88:9: error: 'build' was not declared in this scope
88 | build(u, v, a, b);
| ^~~~~
parks.cpp:10:33: warning: control reaches end of non-void function [-Wreturn-type]
10 | vector<vector<int>> gr(n + 1);
| ^
