| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1073588 | blushingecchigirl | Connecting Supertrees (IOI20_supertrees) | 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 <bits/stdc++.h>
using namespace std;
#define pb push_back
struct dsu {
vector<int> parent, rank;
int size;
dsu(int sz) {
size = sz;
rank.assign(size, 1);
parent.resize(size);
for(int i = 0; i<size; i++) parent[i] = i;
}
int search(int v) {
if(v == parent[v]) return v;
return parent[v] = search(parent[v]);
}
void connect(int v, int u) {
v = search(v);
u = search(u);
if(v == u) return;
if(rank[v]>=rank[u]) parent[u] = v;
else parent[v] = u;
if(rank[v] == rank[u]) rank[v]++;
return;
}
};
void build(std::vector<std::vector<int>> b);
int construct(std::vector<std::vector<int>> p) {
int n = p.size();
bool ctr = 1;
vector<vector<int>> b(n);
for(int i = 0; i<n; i++) b[i].resize(n, 0);
vector<int> a[n];
dsu d = dsu(n);
for(int i = 0; i<n; i++) {
for(int j = 0; j<n; j++) {
if(p[i][j]) d.connect(i, j);
}
}
for(int i = 0; i<n; i++) {
a[d.search(i)].pb(i);
}
for(int i = 0; i<n; i++) {
int sz = a[i].size();
for(int ii = 0; ii<sz; ii++) {
for(int j = 0; j<sz; j++) {
if(p[a[ii]][a[j]] == 0 || p[a[ii]][a[j]] == 3) ctr = 0;
}
}
if(sz<=1) continue;
vector<int> tree[sz], circle;
dsu dd = dsu(sz);
for(int ii = 0; ii<sz; ii++) {
for(int j = 0; j<sz; j++) {
if(p[a[i][ii]][a[i][j]] == 1) dd.connect(ii, j);
}
}
for(int ii = 0; ii<sz; ii++) {
tree[dd.search(ii)].pb(a[i][ii]);
}
for(int ii = 0; ii<sz; ii++) {
if(tree[ii].size() == 0) continue;
if(tree[ii].size()>1) {
for(size_t j = 1; j<tree[ii].size(); j++) b[tree[ii][j]][tree[ii][j-1]] = b[tree[ii][j-1]][tree[ii][j]] = 1;
}
for(size_t iii = 0; iii < tree[ii].size(); iii++) {
for(size_t j = 0; j < tree[ii].size(); j++) {
if(p[tree[ii][iii]][tree[ii][j]] != 1) ctr = 0;
}
}
circle.pb(tree[ii][0]);
}
for(size_t ii = 1; ii<circle.size(); ii++) {
b[circle[ii]][circle[ii-1]] = b[circle[ii-1]][circle[ii]] = 1;
}
if(circle.size()>1) b[circle[0]][circle.back()] = b[circle.back()][circle[0]] = 1;
if(circle.size() == 2) ctr = 0;
}
if(ctr) build(b);
return ctr;
}