//subtask K <= 1000
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,avx,avx2")
#include "island.h"
#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 5;
const int maxk = 1000 + 5;
const int mlog = 17;
const int inf = 1e8;
int n, m, k;
int a[maxn];
vector<int> have[maxk];
int head[maxn];
vector<pair<int,int>> way[maxn];
int h[maxn];
int par[maxn][20], up[maxn][20];
//int ans[maxk][maxk];
int findhead(int x) {
if(head[x]==x) return x;
return head[x] = findhead(head[x]);
}
void dfs(int u, int last) {
//printf("dfs %d %d\n",u,last);
h[u] = h[last] + 1;
for(int i=1;i<=mlog;i++) {
par[u][i] = par[par[u][i-1]][i-1];
up[u][i] = min(up[par[u][i-1]][i-1], up[u][i-1]);
//printf("\tup %d %d = %d\n",u,i,up[u][i]);
}
for(auto tmp : way[u]) {
int v = tmp.first, val = tmp.second;
if(v == last) continue;
par[v][0] = u;
up[v][0] = val;
dfs(v, u);
}
}
int lca(int x, int y) {
int res = m;
if(h[x]<h[y]) swap(x,y);
for(int i=mlog;i>=0;i--) {
if(h[par[x][i]] >= h[y]) {
//printf("par = %d\n",par[x][i]);
//printf("\t*lca <= %d\n",up[x][i]);
res = min(res, up[x][i]);
x = par[x][i];
}
}
if(x==y) return res;
for(int i=mlog;i>=0;i--) {
if(i == 0 || par[x][i] != par[y][i]) {
res = min(res, up[x][i]);
res = min(res, up[y][i]);
//printf("\tlca <= %d\n",up[x][i]);
//printf("\tlca <= %d\n",up[y][i]);
x = par[x][i];
y = par[y][i];
}
}
return res;
}
void Init(int K, vector<int> F, vector<int> S, vector<int> E){
n = F.size(); m = S.size(); k = K;
for(int i=1;i<=n;i++) {
a[i] = F[i-1];
have[a[i]].push_back(i);
}
for(int i=1;i<=n;i++) head[i] = i;
for(int i=m-1;i>=0;i--) {
S[i]++; E[i]++;
if(findhead(S[i])!=findhead(E[i])) {
head[findhead(S[i])] = findhead(E[i]);
way[S[i]].push_back({E[i], i+1});
way[E[i]].push_back({S[i], i+1});
//printf("edge %d %d\n",S[i],E[i]);
}
}
dfs(1,0);
}
int Separate(int A, int B){
if(have[A].empty() || have[B][0].empty()) return 0;
int x = have[A][0], y = have[B][0];
return lca(x,y);
//if((int)have[A].size() >= wow) return ans[A][B] + 1;
//if((int)have[B].size() >= wow) return ans[B][A] + 1;
}
/*
#include <stdio.h>
#include <stdlib.h>
static void my_assert(int TF, const char* message){
if(!TF){ puts(message); exit(0); }
}
int main(){
int N, M, K, Q;
std::vector<int> F, S, E;
my_assert(scanf("%d%d%d%d", &N, &M, &K, &Q) == 4, "Error: Invalid Input");
my_assert(1 <= K && K <= N && N <= 300000, "Error: Invalid Input");
my_assert(N - 1 <= M && M <= 1000000, "Error: Invalid Input");
my_assert(1 <= Q && Q <= 300000, "Error: Invalid Input");
for(int i = 0; i < N; i++){
int a;
my_assert(scanf("%d", &a) == 1, "Error: Invalid Input");
my_assert(0 <= a && a < K, "Error: Invalid Input");
F.push_back(a);
}
for(int i = 0; i < M; i++){
int a, b;
my_assert(scanf("%d%d", &a, &b) == 2, "Error: Invalid Input");
my_assert(0 <= a && a < N && 0 <= b && b < N && a != b, "Error: Invalid Input");
S.push_back(a), E.push_back(b);
}
Init(K, F, S, E);
for(int i = 0; i < Q; i++){
int a, b;
my_assert(scanf("%d%d", &a, &b) == 2, "Error: Invalid Input");
my_assert(0 <= a && a < K && 0 <= b && b < K && a != b, "Error: Invalid Input");
printf("%d\n", Separate(a, b));
}
return 0;
}
*/
Compilation message
island.cpp:2:0: warning: ignoring #pragma comment [-Wunknown-pragmas]
#pragma comment(linker, "/stack:200000000")
island.cpp: In function 'int Separate(int, int)':
island.cpp:91:35: error: request for member 'empty' in 'have[B].std::vector<int>::operator[](0)', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int> >::value_type {aka int}'
if(have[A].empty() || have[B][0].empty()) return 0;
^~~~~
