#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
int n;
struct UF{
vi e;
UF(int n){ e.resize(n,-1);}
int find(int x){ return (e[x] > 0 ? x : find(-e[x])); }
void _union(int a, int b){
int x = find(a);
int y = find(b);
if(x == y) return;
if(e[x] < e[y]) swap(x,y);
e[x] += e[y];
e[y] = -x;
}
};
int construct(vvi p){
n = p.size();
int ban=0;
UF fu(n);
vvi ans(n, vi(n,0));
vvi conect(n, vi());
for(int i=0; i<n; i++){
for(int j=i; j<n; j++){
if(i==j) continue;
if(p[i][j]==1 && ban==0){
ban=1;
}
if(p[i][j]==2 && ban==0){
ban=2;
}
if(p[i][j]!=0){
fu._union(i, j);
}
}
}
for(int i=0; i<n; i++){
for(int j=i; j<n; j++){
if(p[i][j]==0){
if(fu.find(i)==fu.find(j)){
return 0;
}
}else{
int t = fu.find(i);
conect[t].push_back(i);
conect[t].push_back(j);
}
}
}
for(int i=0; i<n; i++){
for(int j=0; j<(int)conect.size(); j++){
ans[i][conect[i][j]]=1;
}
if(ban==2){
ans[conect[i][(int)conect.size()-1]][i]=1;
}
}
build(ans);
return 1;
}
Compilation message
supertrees.cpp: In function 'int construct(vvi)':
supertrees.cpp:63:2: error: 'build' was not declared in this scope
63 | build(ans);
| ^~~~~
