Submission #246586

#	TimeUTC-0	Username	Problem	Language	Result	Execution time	Memory
246586	2020-07-09 16:19:50	santaclaus03	Railway (BOI17_railway)	C++14	100 / 100	378 ms	43760 KiB

railway

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
#include <bits/stdc++.h>
using namespace std;
using ii = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
int n, m, k; 
vvi tree, anc;
vi discovery, finish, v, ans;
map<ii, int> edge_idx;
int t = 0;
void pre(int u, int p) {
    discovery[u] = t++;
    anc[u][0] = p;
    for (int i = 1; i < 20; ++i) anc[u][i] = anc[anc[u][i - 1]][i - 1];
    for (int v : tree[u]) if (v != p) pre(v, u);
    finish[u] = t++;
}
bool is_anc(int a, int b) {
    return discovery[a] <= discovery[b] && finish[b] <= finish[a];
}
int lca(int a, int b) {
    if (is_anc(a, b)) return a;
    if (is_anc(b, a)) return b;
    for (int step = 19; step >= 0; --step) {
        if (!is_anc(anc[a][step], b)) a = anc[a][step];
    }
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 7 / 7
• Subtask 4: 29 / 29
• Subtask 5: 16 / 16
• Subtask 6: 25 / 25