| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 1049378 |
2024-08-08T17:36:47 Z |
PanosPask |
Toll (APIO13_toll) |
C++14 |
|
0 ms |
348 KB |
#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define CHECK_BIT(var, pos) ((var) & (1 << (pos)))
using namespace std;
typedef pair<int, int> pi;
typedef long long ll;
struct DSU {
int N;
vector<int> rep;
vector<int> rank;
void init(int n) {
N = n;
rep.resize(N);
rank.assign(N, 0);
for (int i = 0; i < N; i++) {
rep[i] = i;
}
}
int find(int a) {
if (rep[a] == a) {
return a;
}
return rep[a] = find(rep[a]);
}
bool unite(int a, int b) {
a = find(a);
b = find(b);
if (a == b) {
return false;
}
if (rank[a] < rank[b]) {
swap(a, b);
}
if (rank[a] == rank[b]) {
rank[a]++;
}
rep[b] = a;
return true;
}
};
struct Edge {
int a, b;
int w;
int id;
bool operator < (const Edge& b) {
return this->w < b.w;
}
};
bool idsort(const Edge& a, const Edge& b)
{
return a.id < b.id;
}
struct SuperEdge {
int dest;
int w;
bool is_default;
};
int N, M, K;
vector<int> p;
vector<Edge> edges;
vector<pi> greedy;
vector<vector<pi>> init_list;
vector<bool> used;
vector<bool> vital;
DSU tree;
// Adjacency list and people counter for the compressed MST
vector<vector<SuperEdge>> adj_list;
vector<ll> tot;
vector<int> pos;
// opt[mask]: The MST with the most profit(i.e highest toll prices on Mr. Greedy edges) when considering only the Mr.Greedy edges in mask
vector<vector<vector<SuperEdge>>> opt;
vector<bool> possible;
ll profit = 0;
int maxw;
vector<bool> in_path;
void build_mst(bool save)
{
sort(edges.begin(), edges.end());
DSU graph;
graph.init(N);
for (int i = 0; i < M; i++) {
bool cur = graph.unite(edges[i].a, edges[i].b);
if (save) {
if (cur) {
used[edges[i].id] = true;
init_list[edges[i].a].pb(mp(edges[i].b, edges[i].id));
init_list[edges[i].b].pb(mp(edges[i].a, edges[i].id));
}
}
else {
if (!cur && used[edges[i].id]) {
// This is an edge that has to go when building MST with Mr.Greedy's edges
vital[edges[i].id] = true;
}
}
}
}
void calculate_msts(void)
{
used.assign(N, false);
vital.assign(N, false);
init_list.resize(N);
build_mst(true);
for (int i = 0; i < K; i++) {
edges.pb({greedy[i].first, greedy[i].second, 0, M});
}
build_mst(false);
sort(edges.begin(), edges.end(), idsort);
}
// Run dfs on the initial MST and compress it
void compress(int node, int par)
{
for (auto [neigh, id] : init_list[node]) {
if (neigh == par) {
continue;
}
compress(neigh, node);
if (!vital[id]) {
tree.unite(neigh, node);
}
}
}
void merge_compressed(void)
{
pos.assign(N, -1);
int sz = 0;
for (int i = 0; i < N; i++) {
if (pos[tree.find(i)] == -1) {
pos[tree.find(i)] = sz;
sz++;
adj_list.push_back({});
tot.push_back(0);
}
tot[pos[tree.find(i)]] += p[i];
}
for (int i = 0; i < N; i++) {
for (auto [neigh, id] : init_list[i]) {
if (vital[id]) {
adj_list[pos[tree.find(i)]].push_back({pos[tree.find(neigh)], edges[id].w, true});
}
}
}
}
void read_input(void)
{
scanf("%d %d %d", &N, &M, &K);
edges.resize(M);
for (int i = 0; i < M; i++) {
int u, v, w;
scanf("%d %d %d", &u, &v, &w);
u--; v--;
edges[i] = {u, v, w, i};
}
greedy.resize(K);
for (int i = 0; i < K; i++) {
int u, v;
scanf("%d %d", &u, &v);
u--; v--;
greedy[i] = mp(u, v);
}
p.resize(N);
for (int i = 0; i < N; i++) {
scanf("%d", &p[i]);
}
}
void clear(void)
{
edges.clear();
p.clear();
greedy.clear();
init_list.clear();
used.clear();
vital.clear();
}
void dfs(int node, int par, int dest, int mask)
{
if (node == dest) {
in_path[node] = true;
return;
}
for (auto e : opt[mask][node]) {
if (e.dest == par) {
continue;
}
dfs(e.dest, node, dest, mask);
if (in_path[e.dest] && e.is_default) {
maxw = max(maxw, e.w);
in_path[node] = true;
break;
}
}
}
ll calc(int node, int par, int mask)
{
ll people = tot[node];
for (auto e : opt[mask][node]) {
if (e.dest == par) {
continue;
}
ll res = calc(e.dest, node, mask);
if (e.is_default == false) {
profit += res * e.w;
}
people += res;
}
return people;
}
int main(void)
{
read_input();
calculate_msts();
tree.init(N);
compress(0, -1);
merge_compressed();
clear();
N = adj_list.size();
// Start calculating the MST while including a subset of Mr. Greedy's edges
ll ans = 0;
opt.resize(1 << K);
possible.assign(1 << K, false);
opt[0] = adj_list;
possible[0] = true;
for (int s = 1; s < (1 << K); s++) {
// Find the Mr.Greedy edge to add last
int to_add = 0;
while (!CHECK_BIT(s, to_add)) {
to_add++;
}
int prv = s - (1 << to_add);
if (!possible[prv]) {
continue;
}
int x = pos[tree.find(greedy[to_add].first)];
int y = pos[tree.find(greedy[to_add].second)];
in_path.assign(N, false);
maxw = 0;
dfs(x, -1, y, prv);
if (maxw == 0) {
continue;
}
opt[s].resize(N);
for (int i = 0; i < N; i++) {
for (auto e : opt[prv][i]) {
if (!in_path[i] || !in_path[e.dest]) {
opt[s][i].pb(e);
}
else {
e.w = max(e.w, maxw);
if (e.w == maxw && e.is_default) {
// This is the edge to be removed
continue;
}
opt[s][i].pb(e);
}
}
}
opt[s][x].pb({y, maxw, false});
opt[s][y].pb({x, maxw, false});
profit = 0;
calc(pos[tree.find(0)], -1, s);
ans = max(ans, profit);
}
printf("%lld\n", ans);
return 0;
}
Compilation message
toll.cpp: In function 'void compress(int, int)':
toll.cpp:144:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
144 | for (auto [neigh, id] : init_list[node]) {
| ^
toll.cpp: In function 'void merge_compressed()':
toll.cpp:174:19: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
174 | for (auto [neigh, id] : init_list[i]) {
| ^
toll.cpp: In function 'void read_input()':
toll.cpp:184:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
184 | scanf("%d %d %d", &N, &M, &K);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
toll.cpp:189:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
189 | scanf("%d %d %d", &u, &v, &w);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
toll.cpp:198:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
198 | scanf("%d %d", &u, &v);
| ~~~~~^~~~~~~~~~~~~~~~~
toll.cpp:206:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
206 | scanf("%d", &p[i]);
| ~~~~~^~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
344 KB |
Output is correct |
| 2 |
Correct |
0 ms |
344 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
344 KB |
Output is correct |
| 2 |
Correct |
0 ms |
344 KB |
Output is correct |
| 3 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
344 KB |
Output is correct |
| 2 |
Correct |
0 ms |
344 KB |
Output is correct |
| 3 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
344 KB |
Output is correct |
| 2 |
Correct |
0 ms |
344 KB |
Output is correct |
| 3 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
344 KB |
Output is correct |
| 2 |
Correct |
0 ms |
344 KB |
Output is correct |
| 3 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
