| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 716491 | myrcella | Stations (IOI20_stations) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
//by szh
#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pii pair<int,int>
#define pll pair<long long,long long>
#define pb push_back
#define debug(x) cerr<<#x<<"="<<x<<endl
#define pq priority_queue
#define inf 0x3f
#define rep(i,a,b) for (int i=a;i<(b);i++)
#define MP make_pair
#define SZ(x) (int(x.size()))
#define ll long long
#define mod 1000000007
#define ALL(x) x.begin(),x.end()
void inc(int &a,int b) {a=(a+b)%mod;}
void dec(int &a,int b) {a=(a-b+mod)%mod;}
int lowbit(int x) {return x&(-x);}
ll p0w(ll base,ll p) {ll ret=1;while(p>0){if (p%2ll==1ll) ret=ret*base%mod;base=base*base%mod;p/=2ll;}return ret;}
//#include "stations.h"
const int maxn = 1010;
vector<int> l;
vector <int> edge[maxn];
int dfs(int u,int pos,int flag,int lst) {
int ret = pos;
if (flag==1) l[u] = pos++;
for (int v:edge[u]) {
if (v==lst) continue;
pos += dfs(v,pos,flag^1,u);
}
if (flag==0) l[u] = pos++;
// debug(233),cout<<u<<" "<<l[u]<<endl;
return pos-ret;
}
std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
l.resize(n);
rep(i,0,n-1) {
edge[u[i]].pb(v[i]);
edge[v[i]].pb(u[i]);
}
dfs(0,0,0,-1);
return l;
}
int find_next_station(int s, int t, std::vector<int> c) {
if (c.back()<s) {
rep(i,1,SZ(c)-1) {
if (t>=c[i] and t<c[i+1]) return c[i];
}
if (t>=c.back() and t<s) return c.back();
return c[0];
}
else {
// assert(c[0]>s);
if (t>s and t<=c[0]) return c[0];
rep(i,1,SZ(c)-1) if (t>c[i-1] and t<=c[i]) return c[i];
return c.back();
}
}
static int max_label = 0;
static int r, n, k, q;
static std::vector<int> u, v, labels, answers;
static std::map<int, int> reverse_labels;
static std::vector<std::vector<int>> adjlist;
static int s, t, w;
static std::vector<int> c;
int main() {
assert(scanf("%d", &r) == 1);
for (int tc = 0; tc < r; tc++) {
assert(scanf("%d%d", &n, &k) == 2);
u.resize(n - 1);
v.resize(n - 1);
adjlist.clear();
adjlist.resize(n);
for (int i = 0; i < n - 1; i++) {
assert(scanf("%d%d", &u[i], &v[i]) == 2);
adjlist[u[i]].push_back(v[i]);
adjlist[v[i]].push_back(u[i]);
}
labels = label(n, k, u, v);
if ((int)labels.size() != n) {
printf("Number of labels not equal to %d\n", n);
exit(0);
}
reverse_labels.clear();
for (int i = 0; i < n; i++) {
if (labels[i] < 0 || labels[i] > k) {
printf("Label not in range 0 to %d\n", k);
exit(0);
}
if (reverse_labels.find(labels[i]) != reverse_labels.end()) {
printf("Labels not unique\n");
exit(0);
}
reverse_labels[labels[i]] = i;
if (labels[i] > max_label) {
max_label = labels[i];
}
}
assert(scanf("%d", &q) == 1);
for (int i = 0; i < q; i++) {
assert(scanf("%d%d%d", &s, &t, &w) == 3);
c.clear();
for (int v : adjlist[s]) {
c.push_back(labels[v]);
}
std::sort(c.begin(), c.end());
int answer = find_next_station(labels[s], labels[t], c);
if (!std::binary_search(c.begin(), c.end(), answer)) {
printf("Label %d returned by find_next_station not found in c\n", answer);
exit(0);
}
answers.push_back(reverse_labels[answer]);
}
}
printf("%d\n", max_label);
for (int index : answers) {
printf("%d\n", index);
}
exit(0);
}