#ifdef LOCAL
# define _GLIBCXX_DEBUG
#endif
#include <bits/stdc++.h>
#include <immintrin.h>
#ifndef LOCAL
#pragma GCC optimize("O3")
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("avx,avx2,bmi,bmi2,popcnt,lzcnt,sse,sse2,sse3,ssse3,mmx")
// #pragma GCC target("avx2")
#endif
using namespace std;
using ll = long long;
using ld = long double;
# define x first
# define y second
# define all(x) x.begin(), x.end()
# define rall(x) x.rbegin(), x.rend()
mt19937_64 mt(time(0));
void solve();
void init();
int32_t main() {
#ifndef LOCAL
// cin.tie(nullptr)->sync_with_stdio(false);
#endif
// cout << fixed << setprecision(30);
init();
int t = 1;
// cin >> t;
while (t--) {
solve();
}
}
namespace fastio {
static constexpr uint32_t SZ = 1 << 17;
char ibuf[SZ];
char obuf[SZ];
uint32_t pil = 0, pir = 0, por = 0;
struct Pre {
char num[40000];
constexpr Pre() : num() {
for (int i = 0; i < 10000; i++) {
int n = i;
for (int j = 3; j >= 0; j--) {
num[i * 4 + j] = n % 10 + '0';
n /= 10;
}
}
}
} constexpr pre;
__attribute__((target("avx2"), optimize("O3"))) inline void load() {
memcpy(ibuf, ibuf + pil, pir - pil);
pir = pir - pil + fread(ibuf + pir - pil, 1, SZ - pir + pil, stdin);
pil = 0;
}
__attribute__((target("avx2"), optimize("O3"))) inline void flush() {
fwrite(obuf, 1, por, stdout);
por = 0;
}
inline void read(char &c) { c = ibuf[pil++]; }
template<typename T>
__attribute__((target("avx2"), optimize("O3"))) inline void read(T &x) {
if (pil + 32 > pir) load();
char c;
do
read(c);
while (c < '-');
bool minus = 0;
if (std::is_signed<T>::value) {
if (c == '-') {
minus = 1;
read(c);
}
}
x = 0;
while (c >= '0') {
x = x * 10 + (c & 15);
read(c);
}
if (std::is_signed<T>::value) {
if (minus) x = -x;
}
}
inline void write(char c) { obuf[por++] = c; }
template<typename T>
__attribute__((target("avx2"), optimize("O3"))) inline void write(T x) {
if (por + 32 > SZ) flush();
if (!x) {
write('0');
return;
}
if (std::is_signed<T>::value) {
if (x < 0) {
write('-');
x = -x;
}
}
if (x >= 10000000000000000) {
uint32_t r1 = x % 100000000;
uint64_t q1 = x / 100000000;
uint32_t r2 = q1 % 100000000;
uint32_t q2 = q1 / 100000000;
uint32_t n1 = r1 % 10000;
uint32_t n2 = r1 / 10000;
uint32_t n3 = r2 % 10000;
uint32_t n4 = r2 / 10000;
if (x >= 1000000000000000000) {
uint32_t q3 = (q2 * 20972) >> 21;
uint32_t r3 = q2 - q3 * 100;
uint32_t q4 = (r3 * 205) >> 11;
uint32_t r4 = r3 - q4 * 10;
obuf[por + 0] = '0' + q3;
obuf[por + 1] = '0' + q4;
obuf[por + 2] = '0' + r4;
memcpy(obuf + por + 3, pre.num + (n4 << 2), 4);
memcpy(obuf + por + 7, pre.num + (n3 << 2), 4);
memcpy(obuf + por + 11, pre.num + (n2 << 2), 4);
memcpy(obuf + por + 15, pre.num + (n1 << 2), 4);
por += 19;
} else if (x >= 100000000000000000) {
uint32_t q3 = (q2 * 205) >> 11;
uint32_t r3 = q2 - q3 * 10;
obuf[por + 0] = '0' + q3;
obuf[por + 1] = '0' + r3;
memcpy(obuf + por + 2, pre.num + (n4 << 2), 4);
memcpy(obuf + por + 6, pre.num + (n3 << 2), 4);
memcpy(obuf + por + 10, pre.num + (n2 << 2), 4);
memcpy(obuf + por + 14, pre.num + (n1 << 2), 4);
por += 18;
} else {
obuf[por + 0] = '0' + q2;
memcpy(obuf + por + 1, pre.num + (n4 << 2), 4);
memcpy(obuf + por + 5, pre.num + (n3 << 2), 4);
memcpy(obuf + por + 9, pre.num + (n2 << 2), 4);
memcpy(obuf + por + 13, pre.num + (n1 << 2), 4);
por += 17;
}
} else {
int i = 8;
char buf[12];
while (x >= 10000) {
memcpy(buf + i, pre.num + (x % 10000) * 4, 4);
x /= 10000;
i -= 4;
}
if (x < 100) {
if (x < 10) {
write(char('0' + x));
} else {
obuf[por + 0] = '0' + x / 10;
obuf[por + 1] = '0' + x % 10;
por += 2;
}
} else {
if (x < 1000) {
memcpy(obuf + por, pre.num + (x << 2) + 1, 3);
por += 3;
} else {
memcpy(obuf + por, pre.num + (x << 2), 4);
por += 4;
}
}
memcpy(obuf + por, buf + i + 4, 8 - i);
por += 8 - i;
}
}
inline int getChar() {
if (pil + 32 > pir) load();
return ibuf[pil++]; }
inline int readChar() {
if (pil + 32 > pir) load();
int c = getChar();
while (c != -1 && c <= 32) c = getChar();
return c;
}
inline void read(char *s) {
int c = readChar();
while (c > 32)
*s++ = c, c = getChar();
*s = 0;
}
inline void read(std::string &s) {
s.clear();
int c = readChar();
while (c > 32) s.push_back(c), c = getChar();
}
inline void write(const char *s) {
while (*s) {
if (por + 32 > SZ) flush();
write(*s++);
}
}
inline void write(std::string &s) {
for (auto &i: s) {
if (por + 32 > SZ) flush();
write(i);
}
}
inline void write(double x) {
if (por + 32 > SZ) flush();
if (x < 0)
write('-'), x = -x;
int t = (int) x;
write(t), x -= t;
write('.');
for (int i = 18 - 1; i > 0; i--) {
x *= 10;
t = std::min(9, (int) x);
write('0' + t), x -= t;
}
x *= 10;
t = std::min(9, (int) (x + 0.5));
write('0' + t);
}
template<typename T, typename ...Args>
inline void read(T &x, Args &...args) {
read(x);
read(args...);
}
template<typename T, typename ...Args>
inline void write(T x, Args ...args) {
write(x);
write(args...);
}
struct AutoFlush {
~AutoFlush() { flush(); }
} AutoFlush;
} // namespace fastio
using fastio::read;
using fastio::write;
void init() {}
const int N = 50500, K = 700, M = 500500;
int p[N], sq[M / K][N];
int* pp;
int get(int x) {
return x == pp[x] ? x : pp[x] = get(pp[x]);
}
void merge(int x, int y) {
pp[get(y)] = get(x);
}
struct edge {
int u, v, w;
};
bool operator <(const edge& a, const edge& b) {
return a.w < b.w;
}
void solve() {
int n, m, k, s;
// cin >> n >> m >> k >> s; s--;
read(n, m, k, s); s--;
edge e[M];
int e_size = 0;
unordered_map<ll, int> mp;
int cnt = 0;
for (int i = 0; i < m; i++) {
int u, v, w;
// cin >> u >> v >> w; u--; v--;
read(u, v, w); u--; v--;
if (u > v) {
swap(u, v);
}
if (mp.find(1ll * N * u + v) != mp.end()) {
mp[1ll * N * u + v] = min(mp[1ll * N * u + v], w);
} else {
mp[1ll * N * u + v] = w;
if (u == s || v == s) {
cnt++;
}
}
}
for (auto [p, w] : mp) {
e[e_size++] = {p / N, p % N, w};
}
sort(e, e + e_size);
for (int i = 0; i < n; i++) {
p[i] = i;
}
m = e_size;
int com[M], comm[M], commold[M];
// vector<int> com(m), comm(m + 1), commold(m + 1);
int comps = n, comps_nos = n;
pp = p;
for (int i = 0; i < m; i++) {
if (!(i % K)) {
int ind = i / K;
for (int j = 0; j < n; j++) {
sq[ind][j] = p[j];
}
}
comm[i] = comps;
if (get(e[i].u) != get(e[i].v)) {
comps--;
}
merge(e[i].u, e[i].v);
}
comm[m] = 1;
for (int i = 0; i <= m; i++) {
commold[i] = comm[i];
}
for (int i = 0; i < n; i++) {
p[i] = i;
}
for (int i = 0; i < m; i++) {
com[i] = comps_nos;
if (e[i].v == s || e[i].u == s) {
continue;
}
if (get(e[i].u) != get(e[i].v)) {
comps_nos--;
}
merge(e[i].u, e[i].v);
}
com[m] = comps_nos;
if (comps > 1 || cnt < k || com[m] > k + 1) {
// cout << "-1\n";
write("-1\n");
return;
}
vector<int> good;
for (int j = 0; j < n; j++) {
p[j] = j;
}
int nos = 0, sst = cnt;
int used[N], used_sz = 0;
for (int i = m - 1; i >= 0; i--) {
if (commold[i] != commold[i + 1]) {
int ind = i / K;
comps = comm[ind * K];
used_sz = 0;
for (int j = ind * K; j < i; j++) {
pp = sq[ind];
int u = get(e[j].u), v = get(e[j].v);
pp = p;
u = get(u);
v = get(v);
if (u != v) {
comps--;
p[u] = v;
used[used_sz++] = u;
}
}
for (int i = 0; i < used_sz; i++) {
p[used[i]] = used[i];
}
} else {
comps = 1;
}
int is_s = 0;
if (e[i].v == s || e[i].u == s) {
is_s = 1;
}
if (comps > 1 || sst - is_s < k || com[i] - nos > k + 1) {
if (e[i].v != s && e[i].u != s) {
nos++;
}
good.push_back(i);
for (int j = 0, jj = 0; jj < i; j++, jj += K) {
pp = sq[j];
int u = get(e[i].u), v = get(e[i].v);
if (u != v) {
comm[jj]--;
sq[j][v] = u;
}
// merge(u, v, sq[j]);
}
} else if (is_s) {
sst--;
}
}
ll ans = 0;
for (int i : good) {
ans += e[i].w;
}
// cout << ans << '\n';
write(ans, '\n');
}
Compilation message
ho_t1.cpp: In function 'void solve()':
ho_t1.cpp:305:26: warning: narrowing conversion of '(((long long int)p) / ((long long int)((int)N)))' from 'long long int' to 'int' [-Wnarrowing]
305 | e[e_size++] = {p / N, p % N, w};
| ~~^~~
ho_t1.cpp:305:33: warning: narrowing conversion of '(((long long int)p) % ((long long int)((int)N)))' from 'long long int' to 'int' [-Wnarrowing]
305 | e[e_size++] = {p / N, p % N, w};
| ~~^~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
22 ms |
24668 KB |
Execution killed with signal 6 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
22 ms |
24668 KB |
Execution killed with signal 6 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
22 ms |
24668 KB |
Execution killed with signal 6 |
| 2 |
Halted |
0 ms |
0 KB |
- |
