/*
I find it wholesome to be alone the greater part of the time.
To be in company, even with the best, is soon wearisome and dissipating.
I love to be alone.
I never found the companion that was so companionable as solitude.
*/
#include <bits/stdc++.h>
#define pb push_back
#define fi first
#define se second
#define faster ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
using ll = long long;
using ld = long double;
using pii = pair <int, int>;
mt19937_64 Rand(chrono::steady_clock::now().time_since_epoch().count());
const int maxN = 1e5 + 1;
//const int Mod = 1e9 + 7;
//const int inf =
int n, m, q;
struct TDSU{
vector <pii> save;
vector <int> lab;
TDSU(){}
TDSU(int _n){
lab.resize(_n, -1);
}
inline void resize(int _n){
lab.resize(_n, -1);
}
inline int find_set(int u){
if (lab[u] < 0) return u;
return lab[u] = find_set(lab[u]);
}
inline int find(int u){
if (lab[u] < 0) return u;
return find(lab[u]);
}
inline bool unite(int u, int v){
u = find_set(u);
v = find_set(v);
if (u == v) return 0;
if (lab[u] > lab[v]) swap(u, v);
save.pb({v, lab[v]});
lab[u] += lab[v];
lab[v] = u;
return 1;
}
inline void undo(){
int v = save.back().fi;
int u = lab[v];
lab[v] = save.back().se;
lab[u] -= lab[v];
save.pop_back();
}
inline void clear(){
lab.clear();
save.clear();
}
inline void reset(int _n){
clear();
resize(_n);
}
inline void roll_back(int _n){
while (save.size() > _n) undo();
}
};
vector <int> adj[maxN];
int depth[maxN];
int lift[maxN][20], rmq[maxN][20];
void dfs(int u, int p){
depth[u] = depth[p] + 1;
rmq[u][0] = abs(p - u);
lift[u][0] = p;
for (int i = 1; i < 20; ++i){
lift[u][i] = lift[lift[u][i - 1]][i - 1];
rmq[u][i] = min(rmq[u][i - 1], rmq[lift[u][i - 1]][i - 1]);
}
for (int i: adj[u]){
if (i == p) continue;
dfs(i, u);
}
}
inline int lca(int u, int v){
if (depth[u] < depth[v]) swap(u, v);
int k = depth[u] - depth[v];
int res = m + 1;
while (k){
int t = __builtin_ctz(k);
res = min(res, rmq[u][t]);
u = lift[u][t];
k -= 1 << t;
}
if (u == v) return m - res + 1;
for (int i = 19; i >= 0; --i){
if (lift[u][i] != lift[v][i]){
res = min(res, rmq[u][i]);
res = min(res, rmq[v][i]);
u = lift[u][i];
v = lift[v][i];
}
}
res = min(res, rmq[u][0]);
res = min(res, rmq[v][0]);
return m - res + 1;
}
void Init(){
cin >> n >> m >> q;
TDSU dsu(n + 1);
for (int i = m; i >= 1; --i){
for (int j = 2 * i; j <= n; j += i){
if (dsu.unite(j - i, j)){
adj[j - i].pb(j);
adj[j].pb(j - i);
}
}
}
dfs(1, 0);
while (q--){
int a, b;
cin >> a >> b;
cout << lca(a, b) << "\n";
}
}
#define debug
#define taskname "test"
signed main(){
faster
if (fopen(taskname".inp", "r")){
freopen(taskname".inp", "r", stdin);
freopen(taskname".out", "w", stdout);
}
int tt = 1;
//cin >> tt;
while (tt--){
Init();
}
if (fopen("timeout.txt", "r")){
ofstream timeout("timeout.txt");
timeout << signed(double(clock()) / CLOCKS_PER_SEC * 1000);
timeout.close();
#ifndef debug
cerr << "Time elapsed: " << signed(double(clock()) / CLOCKS_PER_SEC * 1000) << "ms\n";
#endif // debug
}
}
Compilation message
pictionary.cpp: In member function 'void TDSU::roll_back(int)':
pictionary.cpp:66:28: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
66 | while (save.size() > _n) undo();
| ~~~~~~~~~~~~^~~~
pictionary.cpp: In function 'int main()':
pictionary.cpp:135:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
135 | freopen(taskname".inp", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
pictionary.cpp:136:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
136 | freopen(taskname".out", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
2772 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
6 ms |
2900 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
19 ms |
3580 KB |
Output is correct |
| 2 |
Correct |
20 ms |
3652 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
27 ms |
4096 KB |
Output is correct |
| 2 |
Correct |
25 ms |
3924 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
27 ms |
8008 KB |
Output is correct |
| 2 |
Correct |
35 ms |
7924 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
31 ms |
9904 KB |
Output is correct |
| 2 |
Correct |
36 ms |
10768 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
53 ms |
13232 KB |
Output is correct |
| 2 |
Correct |
47 ms |
13472 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
68 ms |
16708 KB |
Output is correct |
| 2 |
Correct |
77 ms |
18332 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
82 ms |
20200 KB |
Output is correct |
| 2 |
Correct |
96 ms |
22416 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
104 ms |
24896 KB |
Output is correct |
| 2 |
Correct |
117 ms |
24860 KB |
Output is correct |
