牛客寒假算法基礎訓練營3 G.糖果

思路：

#include<bits/stdc++.h>
using namespace std;
#define ll long long 
const int mod = 1e9 + 7;
ll pre[1010000];
ll a[1000010];
ll find(ll a)
{
  if(pre[a] != a)
  return pre[a] = find(pre[a]);
  return pre[a];
} 
void join(ll x, ll y)
{
  x = find(x),y = find(y);
  pre[x] = y;
  a[y] = max(a[x], a[y]);
} 
int main()
{
  ll n,m;
  scanf("%lld%lld",&n,&m);
  for(ll i = 1; i <= n; i++)
  {
    scanf("%lld",&a[i]);
    pre[i] = i;
  }
  
  while(m--)
  {
    ll v,u;
    scanf("%lld%lld",&v,&u);
    join(v,u);
  }
  ll ans = 0;
  for(int i = 1; i <= n; i++)
  {
    ans += (a[find(i)]);
  }
  printf("%lld\n",ans);
}