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| struct edge{char x, y; int d;};
bool cmp(const edge& a, const edge& b){
return a.d < b.d;
}
vector<edge> v;
int n, pre[maxn];
void init(){
for (int i = 0; i < maxn; i++) pre[i] = i;
}
int find(int x){return x == pre[x] ? x : pre[x] = find(pre[x]);}
void join(int x, int y){
x = find(x), y = find(y);
pre[x] = y;
}
int kruskal(){
sort(v.begin(), v.end(), cmp);
int ans = 0;
for (int i = 0, a, b; i < v.size(); i++){
a = find(v[i].x - 'A'), b = find(v[i].y - 'A');
if (a == b) continue;
join(a, b); ans += v[i].d;
}
return ans;
}
|