#include<bits/stdc++.h>
#define ms(v) memset(v, -1, sizeof v)
#define pb push_back
#define mp make_pair
#define N 200010
using namespace std;
int n, m, q;
int pai[N], edge[N], sz[N], lvl[N];
void init(int x){
pai[x] = x;
sz[x] = 1;
}
int find(int x){
return (x == pai[x] ? x : find(pai[x]));
}
void join(int a, int b, int d){
a = find(a);
b = find(b);
if(a == b) return;
if(sz[a] < sz[b]) swap(a, b);
pai[b] = a;
sz[a] += sz[b];
edge[b] = d;
return;
}
int lca(int a){
return lvl[a] = (a == pai[a] ? 0 : lca(pai[a]) + 1);
}
int xdfs(int a, int b){
if(find(a) != find(b)) return -1;
int resa = 0, resb = 0;
if(lvl[a] < lvl[b]) swap(a, b);
while(lvl[a] > lvl[b]){
if(resa < edge[a]) resa = edge[a];
a = pai[a];
}
while(a != b){
if(resa < edge[a]) resa = edge[a];
if(resb < edge[b]) resb = edge[b];
a = pai[a];
b = pai[b];
}
return max(resa, resb);
}
int main(){
ios::sync_with_stdio(false); cin.tie(0);
cin >> n >> m >> q;
for(int i = 1;i <= n;i++){
init(i);
}
for (int i = m; i >= 1; i--)
for (int j = i; j <= n; j += i)
join(j, i, m-i+1);
for(int i = 1;i <= n;i++) lca(i);
for(int i = 1;i <= q;i++){
int a, b;
cin >> a >> b;
cout << dfs(a, b) << "\n";
}
return 0;
}
Compilation message
pictionary.cpp: In function 'int main()':
pictionary.cpp:80:17: error: 'dfs' was not declared in this scope; did you mean 'xdfs'?
80 | cout << dfs(a, b) << "\n";
| ^~~
| xdfs
