cplib-cpp
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data_structure/test/radix_heap_array.dijkstra.test.cpp
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- Last update: 2022-01-08 20:23:44+09:00
- Problem: https://judge.yosupo.jp/problem/shortest_path
Depends on
- Array-like radix heap with decrease query（chmin 操作が可能な基数ヒープ）
(data_structure/radix_heap_array.hpp)
- 高速標準入力
(utilities/reader.hpp)
Code
#define PROBLEM "https://judge.yosupo.jp/problem/shortest_path"
#include "../radix_heap_array.hpp"
#include "../../utilities/reader.hpp"
#include <iostream>
#include <limits>
#include <utility>
#include <vector>
using namespace std;
int main() {
cin.tie(nullptr), ios::sync_with_stdio(false);
int N = rdi(), M = rdi(), s = rdi(), t = rdi();
vector<vector<pair<int, unsigned>>> to(N);
while (M--) {
int a = rdi(), b = rdi(), c = rdi();
to[b].emplace_back(a, c);
}
vector<unsigned long long> dist(N, numeric_limits<unsigned long long>::max());
vector<int> prv(N, -1);
dist[t] = 0;
radix_heap_array<unsigned long long> pq;
pq.chmin(0, t);
while (!pq.empty()) {
int now = pq.argmin_pop();
if (now == s) break;
for (const auto &nx : to[now]) {
int nxt = nx.first;
if (dist[nxt] > dist[now] + nx.second) {
dist[nxt] = dist[now] + nx.second;
prv[nxt] = now;
pq.chmin(dist[nxt], nxt);
}
}
}
if (dist[s] == numeric_limits<unsigned long long>::max()) {
cout << "-1\n";
return 0;
}
std::vector<int> path;
for (int now = s; now != -1; now = prv[now]) path.push_back(now);
cout << dist[s] << ' ' << path.size() - 1 << '\n';
for (int i = 1; i < int(path.size()); i++) cout << path[i - 1] << ' ' << path[i] << '\n';
}#line 1 "data_structure/test/radix_heap_array.dijkstra.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/shortest_path"
#line 2 "data_structure/radix_heap_array.hpp"
#include <array>
#include <limits>
#include <type_traits>
#include <utility>
#include <vector>
template <class Uint> class radix_heap_array {
int sz;
Uint last;
std::array<std::vector<std::pair<Uint, int>>, std::numeric_limits<Uint>::digits + 1> v;
struct smallpii {
unsigned b : 7;
int j : 25;
};
std::vector<smallpii> i2bj;
template <class U, typename std::enable_if<sizeof(U) == 4>::type * = nullptr>
static inline unsigned bucket(U x) noexcept {
return x ? 32 - __builtin_clz(x) : 0;
}
template <class U, typename std::enable_if<sizeof(U) == 8>::type * = nullptr>
static inline unsigned bucket(U x) noexcept {
return x ? 64 - __builtin_clzll(x) : 0;
}
void pull() {
if (!v[0].empty()) return;
int b = 1;
while (v[b].empty()) ++b;
last = v[b].back().first;
for (int j = 0; j < int(v[b].size()); j++) last = std::min(last, v[b][j].first);
for (int j = 0; j < int(v[b].size()); j++) {
int i = v[b][j].second;
auto bnxt = bucket(v[b][j].first ^ last);
i2bj[i] = {bnxt, int(v[bnxt].size())}, v[bnxt].emplace_back(std::move(v[b][j]));
}
v[b].clear();
}
public:
radix_heap_array() : sz(0), last(0) {}
bool empty() const noexcept { return sz == 0; }
int argmin_pop() {
pull(), --sz;
int i = v[0].back().second;
i2bj[i].j = -1;
v[0].pop_back();
return i;
}
void chmin(Uint vnew, int i) {
if (i >= int(i2bj.size())) i2bj.resize(i + 1, {0, -1});
if (i2bj[i].j < 0) {
auto b = bucket(vnew ^ last);
++sz, i2bj[i] = {b, int(v[b].size())}, v[b].emplace_back(vnew, i);
} else if (v[i2bj[i].b][i2bj[i].j].first > vnew) {
auto bold = i2bj[i].b, bnew = bucket(vnew ^ last);
if (bnew < bold) {
int ilast = v[bold].back().second, j = i2bj[i].j;
std::swap(v[bold][j], v[bold].back());
i2bj[ilast].j = j, i2bj[i] = {bnew, int(v[bnew].size())};
v[bnew].emplace_back(vnew, i), v[bold].pop_back();
} else {
v[bold][i2bj[i].j].first = vnew;
}
}
}
void pop() { argmin_pop(); }
std::pair<Uint, int> top() { return pull(), v[0].back(); }
[[deprecated("NOT usual emplace() opeation!")]] void emplace(Uint vnew, int i) {
chmin(vnew, i);
}
void clear() noexcept { sz = 0, last = 0, i2bj.clear(); }
};
#line 2 "utilities/reader.hpp"
#include <cstdio>
#include <string>
// CUT begin
template <typename T> T rd_integer() {
T ret = 0;
bool minus = false;
char c = getchar_unlocked();
while (!isdigit(c)) minus |= (c == '-'), c = getchar_unlocked();
while (isdigit(c)) ret = (ret << 1) + (ret << 3) + (c ^ 48), c = getchar_unlocked();
return minus ? -ret : ret;
}
int rdi() { return rd_integer<int>(); }
long long rdll() { return rd_integer<long long>(); }
std::string rdstr() {
std::string ret;
char c = getchar_unlocked();
while (!isgraph(c)) c = getchar_unlocked();
while (isgraph(c)) ret += c, c = getchar_unlocked();
return ret;
}
#line 4 "data_structure/test/radix_heap_array.dijkstra.test.cpp"
#include <iostream>
#line 8 "data_structure/test/radix_heap_array.dijkstra.test.cpp"
using namespace std;
int main() {
cin.tie(nullptr), ios::sync_with_stdio(false);
int N = rdi(), M = rdi(), s = rdi(), t = rdi();
vector<vector<pair<int, unsigned>>> to(N);
while (M--) {
int a = rdi(), b = rdi(), c = rdi();
to[b].emplace_back(a, c);
}
vector<unsigned long long> dist(N, numeric_limits<unsigned long long>::max());
vector<int> prv(N, -1);
dist[t] = 0;
radix_heap_array<unsigned long long> pq;
pq.chmin(0, t);
while (!pq.empty()) {
int now = pq.argmin_pop();
if (now == s) break;
for (const auto &nx : to[now]) {
int nxt = nx.first;
if (dist[nxt] > dist[now] + nx.second) {
dist[nxt] = dist[now] + nx.second;
prv[nxt] = now;
pq.chmin(dist[nxt], nxt);
}
}
}
if (dist[s] == numeric_limits<unsigned long long>::max()) {
cout << "-1\n";
return 0;
}
std::vector<int> path;
for (int now = s; now != -1; now = prv[now]) path.push_back(now);
cout << dist[s] << ' ' << path.size() - 1 << '\n';
for (int i = 1; i < int(path.size()); i++) cout << path[i - 1] << ' ' << path[i] << '\n';
}