#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
//typedef __uint128_t L;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
cerr << " " << H;
debug_out(T...);
}
#define debug(...) cerr << "(" << #__VA_ARGS__ << "):", debug_out(__VA_ARGS__)
#define all(x) x.begin(), x.end()
#define MP(x, y) make_pair(x, y)
#define F first
#define S second
const int maxn = 1e6 + 10;
const int lg = 20;
const int maxm = 20;
const int mask = (1 << 20);
const int inf = 1e9;
int n, m, S, T, edge[maxm][3], comp[maxn], cnt, sz, par[mask][maxm+1], dis[maxm+1][maxm+1], h[maxn], pare[maxn][lg], dp[mask][maxm+1];
vector<int> g[maxn], G[maxm+1];
bool vis[maxn];
int first[maxn], to[maxn << 1], nxt[maxn << 1], ecnt;
void add(int u, int v){
nxt[++ecnt] = first[u];
to[ecnt] = v;
first[u] = ecnt;
}
void dfs(int v,int p = -1){
pare[v][0] = p;
for (int i = 1; i < lg; i++) if (pare[v][i-1] != -1) pare[v][i] = pare[pare[v][i-1]][i-1];
for (int i = first[v]; i; i = nxt[i]){
int u = to[i];
if (u != p){
h[u] = h[v] + 1;
dfs(u, v);
}
}
}
int getpar(int v, int x){
for (int i = 0; i < lg; i++){
if ((x >> i) & 1) v = pare[v][i];
}
return v;
}
int lca(int u, int v){
if (h[u] < h[v]) swap(u, v);
u = getpar(u, h[u] - h[v]);
if (u == v) return u;
for(int i = lg - 1; ~i; i--){
if (pare[v][i] != pare[u][i]){
v = pare[v][i];
u = pare[u][i];
}
}
return pare[u][0];
}
void getcomp(int v, int p = -1){
vis[v] = true;
comp[v] = cnt;
for (auto u: g[v]) if (u != p) getcomp(u, v);
}
void getpar(int v, int *par, int p = -1){
vis[v] = true;
par[v] = sz;
for (auto u : G[v]) if (u != p) getpar(u, par, v);
}
int main(){
//ios_base::sync_with_stdio(false); cin.tie(0);
memset(pare, -1, sizeof pare);
scanf("%d%d%d", &n, &S, &T);
for (int i = 1; i < n; i++){
int u, v, w; scanf("%d%d%d", &u, &v, &w);
add(u, v);
add(v, u);
if (w == 0){
g[u].push_back(v);
g[v].push_back(u);
}
else{
edge[m][0] = u;
edge[m][1] = v;
edge[m][2] = w;
m++;
}
}
dfs(S);
for (int i = 0; i < m; i++){
if (h[edge[i][0]] > h[edge[i][1]]) swap(edge[i][0], edge[i][1]);
}
for (int i = 0; i <= m; i++){
for (int j = 0; j <= m; j++){
int v = (i == m? S: edge[i][0]);
int u = (j == m? T: edge[j][0]);
if (j != m){
dis[i][j] = h[v] + h[u] + 2 * h[edge[j][2]] - 2 * h[lca(v, edge[j][2])] - 2 * h[lca(u, edge[j][2])];
}
else{
dis[i][j] = h[v] + h[u] - 2 * h[lca(u, v)];
}
}
}
for (int i = 1; i <= n; i++){
if (!vis[i]){
getcomp(i);
cnt++;
}
}
for (int i = 0; i < (1 << m); i++){
for (int j = 0; j < m+1; j++){
G[j].clear();
vis[j] = false;
}
for (int j = 0; j < m; j++){
if (!((i >> j) & 1)){
G[comp[edge[j][0]]].push_back(comp[edge[j][1]]);
G[comp[edge[j][1]]].push_back(comp[edge[j][0]]);
}
}
sz = 0;
for (int j = 0; j < m+1; j++){
if (!vis[j]){
sz++;
getpar(j, par[i]);
}
}
}
for (int i = 0; i <= m; i++){
dp[0][i] = dis[i][m];
}
for (int msk = 1; msk < (1 << m); msk++){
for (int i = 0; i <= m; i++){
int v = (i == m? S: edge[i][0]);
dp[msk][i] = inf;
if (par[msk][comp[T]] == par[msk][comp[v]]){
dp[msk][i] = dis[i][m];
continue;
}
for (int tmp = msk; tmp; tmp ^= tmp & -tmp){
int j = __builtin_ctz(tmp);
if (par[msk][comp[edge[j][2]]] == par[msk][comp[v]] && par[msk][comp[edge[j][0]]] == par[msk][comp[v]]){
dp[msk][i] = min(dp[msk][i], dp[msk^(1 << j)][j] + dis[i][j]);
}
}
}
}
printf("%d\n", (dp[(1 << m) - 1][m] == inf? -1: dp[(1 << m) - 1][m]));
return 0;
}
Compilation message
Main.cpp: In function 'int main()':
Main.cpp:92:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
92 | scanf("%d%d%d", &n, &S, &T);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:94:21: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
94 | int u, v, w; scanf("%d%d%d", &u, &v, &w);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
40 ms |
102096 KB |
Output is correct |
2 |
Correct |
43 ms |
102068 KB |
Output is correct |
3 |
Correct |
123 ms |
109648 KB |
Output is correct |
4 |
Correct |
104 ms |
109668 KB |
Output is correct |
5 |
Correct |
101 ms |
109644 KB |
Output is correct |
6 |
Correct |
98 ms |
109572 KB |
Output is correct |
7 |
Correct |
101 ms |
109652 KB |
Output is correct |
8 |
Correct |
102 ms |
109672 KB |
Output is correct |
9 |
Correct |
102 ms |
109848 KB |
Output is correct |
10 |
Correct |
98 ms |
109744 KB |
Output is correct |
11 |
Correct |
98 ms |
109724 KB |
Output is correct |
12 |
Correct |
113 ms |
111272 KB |
Output is correct |
13 |
Correct |
99 ms |
110932 KB |
Output is correct |
14 |
Correct |
99 ms |
110612 KB |
Output is correct |
15 |
Correct |
99 ms |
111364 KB |
Output is correct |
16 |
Correct |
114 ms |
111896 KB |
Output is correct |
17 |
Correct |
125 ms |
111996 KB |
Output is correct |
18 |
Correct |
111 ms |
112280 KB |
Output is correct |
19 |
Correct |
110 ms |
115556 KB |
Output is correct |
20 |
Correct |
117 ms |
115400 KB |
Output is correct |
21 |
Correct |
141 ms |
115324 KB |
Output is correct |
22 |
Correct |
41 ms |
102060 KB |
Output is correct |
23 |
Correct |
41 ms |
102112 KB |
Output is correct |
24 |
Correct |
41 ms |
102108 KB |
Output is correct |
25 |
Correct |
47 ms |
102064 KB |
Output is correct |
26 |
Correct |
42 ms |
102032 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
39 ms |
102088 KB |
Output is correct |
2 |
Correct |
41 ms |
102012 KB |
Output is correct |
3 |
Correct |
41 ms |
102192 KB |
Output is correct |
4 |
Correct |
43 ms |
102256 KB |
Output is correct |
5 |
Correct |
717 ms |
188732 KB |
Output is correct |
6 |
Correct |
668 ms |
188752 KB |
Output is correct |
7 |
Correct |
711 ms |
188840 KB |
Output is correct |
8 |
Correct |
672 ms |
188700 KB |
Output is correct |
9 |
Correct |
706 ms |
188808 KB |
Output is correct |
10 |
Correct |
545 ms |
188816 KB |
Output is correct |
11 |
Correct |
594 ms |
188816 KB |
Output is correct |
12 |
Correct |
542 ms |
188732 KB |
Output is correct |
13 |
Correct |
533 ms |
188748 KB |
Output is correct |
14 |
Correct |
559 ms |
188728 KB |
Output is correct |
15 |
Correct |
728 ms |
188772 KB |
Output is correct |
16 |
Correct |
645 ms |
188828 KB |
Output is correct |
17 |
Correct |
736 ms |
188784 KB |
Output is correct |
18 |
Correct |
571 ms |
188924 KB |
Output is correct |
19 |
Correct |
527 ms |
188856 KB |
Output is correct |
20 |
Correct |
566 ms |
189064 KB |
Output is correct |
21 |
Correct |
530 ms |
188932 KB |
Output is correct |
22 |
Correct |
541 ms |
189160 KB |
Output is correct |
23 |
Correct |
552 ms |
189104 KB |
Output is correct |
24 |
Correct |
543 ms |
189344 KB |
Output is correct |
25 |
Correct |
1026 ms |
274488 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
40 ms |
102096 KB |
Output is correct |
2 |
Correct |
43 ms |
102068 KB |
Output is correct |
3 |
Correct |
123 ms |
109648 KB |
Output is correct |
4 |
Correct |
104 ms |
109668 KB |
Output is correct |
5 |
Correct |
101 ms |
109644 KB |
Output is correct |
6 |
Correct |
98 ms |
109572 KB |
Output is correct |
7 |
Correct |
101 ms |
109652 KB |
Output is correct |
8 |
Correct |
102 ms |
109672 KB |
Output is correct |
9 |
Correct |
102 ms |
109848 KB |
Output is correct |
10 |
Correct |
98 ms |
109744 KB |
Output is correct |
11 |
Correct |
98 ms |
109724 KB |
Output is correct |
12 |
Correct |
113 ms |
111272 KB |
Output is correct |
13 |
Correct |
99 ms |
110932 KB |
Output is correct |
14 |
Correct |
99 ms |
110612 KB |
Output is correct |
15 |
Correct |
99 ms |
111364 KB |
Output is correct |
16 |
Correct |
114 ms |
111896 KB |
Output is correct |
17 |
Correct |
125 ms |
111996 KB |
Output is correct |
18 |
Correct |
111 ms |
112280 KB |
Output is correct |
19 |
Correct |
110 ms |
115556 KB |
Output is correct |
20 |
Correct |
117 ms |
115400 KB |
Output is correct |
21 |
Correct |
141 ms |
115324 KB |
Output is correct |
22 |
Correct |
41 ms |
102060 KB |
Output is correct |
23 |
Correct |
41 ms |
102112 KB |
Output is correct |
24 |
Correct |
41 ms |
102108 KB |
Output is correct |
25 |
Correct |
47 ms |
102064 KB |
Output is correct |
26 |
Correct |
42 ms |
102032 KB |
Output is correct |
27 |
Correct |
39 ms |
102088 KB |
Output is correct |
28 |
Correct |
41 ms |
102012 KB |
Output is correct |
29 |
Correct |
41 ms |
102192 KB |
Output is correct |
30 |
Correct |
43 ms |
102256 KB |
Output is correct |
31 |
Correct |
717 ms |
188732 KB |
Output is correct |
32 |
Correct |
668 ms |
188752 KB |
Output is correct |
33 |
Correct |
711 ms |
188840 KB |
Output is correct |
34 |
Correct |
672 ms |
188700 KB |
Output is correct |
35 |
Correct |
706 ms |
188808 KB |
Output is correct |
36 |
Correct |
545 ms |
188816 KB |
Output is correct |
37 |
Correct |
594 ms |
188816 KB |
Output is correct |
38 |
Correct |
542 ms |
188732 KB |
Output is correct |
39 |
Correct |
533 ms |
188748 KB |
Output is correct |
40 |
Correct |
559 ms |
188728 KB |
Output is correct |
41 |
Correct |
728 ms |
188772 KB |
Output is correct |
42 |
Correct |
645 ms |
188828 KB |
Output is correct |
43 |
Correct |
736 ms |
188784 KB |
Output is correct |
44 |
Correct |
571 ms |
188924 KB |
Output is correct |
45 |
Correct |
527 ms |
188856 KB |
Output is correct |
46 |
Correct |
566 ms |
189064 KB |
Output is correct |
47 |
Correct |
530 ms |
188932 KB |
Output is correct |
48 |
Correct |
541 ms |
189160 KB |
Output is correct |
49 |
Correct |
552 ms |
189104 KB |
Output is correct |
50 |
Correct |
543 ms |
189344 KB |
Output is correct |
51 |
Correct |
1026 ms |
274488 KB |
Output is correct |
52 |
Correct |
1316 ms |
170004 KB |
Output is correct |
53 |
Correct |
1303 ms |
170236 KB |
Output is correct |
54 |
Correct |
1285 ms |
168276 KB |
Output is correct |
55 |
Correct |
1298 ms |
167344 KB |
Output is correct |
56 |
Correct |
1307 ms |
168372 KB |
Output is correct |
57 |
Correct |
1355 ms |
169720 KB |
Output is correct |
58 |
Correct |
41 ms |
102080 KB |
Output is correct |
59 |
Correct |
41 ms |
102152 KB |
Output is correct |
60 |
Correct |
45 ms |
102064 KB |
Output is correct |
61 |
Correct |
1387 ms |
169632 KB |
Output is correct |
62 |
Correct |
1452 ms |
188736 KB |
Output is correct |
63 |
Correct |
1397 ms |
182904 KB |
Output is correct |
64 |
Correct |
116 ms |
111352 KB |
Output is correct |
65 |
Correct |
145 ms |
111528 KB |
Output is correct |
66 |
Correct |
1335 ms |
174780 KB |
Output is correct |
67 |
Correct |
1387 ms |
174452 KB |
Output is correct |
68 |
Correct |
1734 ms |
256964 KB |
Output is correct |
69 |
Correct |
1737 ms |
257320 KB |
Output is correct |
70 |
Correct |
1749 ms |
256780 KB |
Output is correct |
71 |
Correct |
1684 ms |
256708 KB |
Output is correct |
72 |
Correct |
1676 ms |
256836 KB |
Output is correct |
73 |
Correct |
1590 ms |
258200 KB |
Output is correct |
74 |
Correct |
1707 ms |
258776 KB |
Output is correct |
75 |
Correct |
1622 ms |
258364 KB |
Output is correct |
76 |
Correct |
1626 ms |
259540 KB |
Output is correct |
77 |
Correct |
1605 ms |
258324 KB |
Output is correct |
78 |
Correct |
1889 ms |
264556 KB |
Output is correct |
79 |
Correct |
1862 ms |
263280 KB |
Output is correct |
80 |
Correct |
1936 ms |
262352 KB |
Output is correct |
81 |
Correct |
1925 ms |
275416 KB |
Output is correct |
82 |
Correct |
1851 ms |
277016 KB |
Output is correct |
83 |
Correct |
1868 ms |
276548 KB |
Output is correct |
84 |
Correct |
1902 ms |
285340 KB |
Output is correct |
85 |
Correct |
1861 ms |
315624 KB |
Output is correct |
86 |
Correct |
1879 ms |
314672 KB |
Output is correct |
87 |
Correct |
1949 ms |
315488 KB |
Output is correct |