| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1024600 | thinknoexit | City Mapping (NOI18_citymapping) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include "citymapping.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 1010;
int n;
ll dis[N][N];
int A[N], B[N], W[N], tot;
ll d(int i, int j) {
if (i == j) return 0;
if (!dis[i][j]) return dis[i][j] = dis[j][i] = get_distance(i, j);
return dis[i][j];
}
void play(vector<int>& v, int P) {
int m = v.size();
if (m == 1) return;
ll mx = 0;
int U = 0, V = 0;
for (auto& x : v) {
if (d(P, x) > mx) {
mx = d(P, x);
U = x;
}
}
mx = 0;
for (auto& x : v) {
if (d(U, x) > mx) {
mx = d(U, x);
V = x;
}
}
// U, V is leaf
ll all = d(U, V);
vector<pair<ll, int>> in, rem;
for (auto& x; v) {
if (d(U, x) + d(x, V) == all) in.push_back({ d(U, x), x });
else {
ll extra = (d(U, x) + d(x, V) - all) / 2;
rem.push_back({ d(U, x) - extra, x });
}
}
sort(in.begin(), in.end());
sort(rem.begin(), rem.end());
vector<vector<int>> r;
vector<int> p2;
int p = 0;
for (int i = 1;i < (int)in.size();i++) {
A[tot] = in[i - 1].second;
B[tot] = in[i].second;
W[tot] = in[i].first - in[i - 1].first;
tot++;
vector<int> nw;
ll mn = LLONG_MAX;
int idx = 0;
while (p < (int)rem.size() && rem[p].first == in[i].first) {
int vl = rem[p].second;
ll extra = (d(U, vl) + d(vl, V) - all) / 2;
if (extra < mn) {
mn = extra;
idx = vl;
}
nw.push_back(vl);
p++;
}
if (!nw.empty()) {
A[tot] = idx;
B[tot] = in[i].second;
W[tot] = mn;
tot++;
for (auto& x : nw) {
dis[idx][x] = dis[x][idx] = d(U, x) - mn;
}
r.push_back(nw);
p2.push_back(idx);
}
}
for (int i = 0;i < (int)r.size();i++) {
play(r[i], p2[i]);
}
}
void find_roads(int NN, int Q, int A[], int B[], int W[]) {
n = NN;
vector<int> init(n);
iota(init.begin(), init.end(), 1);
play(init, 1);
for (int i = 0;i < n - 1;i++) {
A[i] = ::A[i];
B[i] = ::B[i];
W[i] = ::W[i];
//cout << A[i] << ' ' << B[i] << ' ' << W[i] << '\n';
}
return;
}