传送门
Luogu
解题思路
线段树合并板子题（也可以 dsu on the tree）
好像没什么好讲的，就是要注意开 long long 。
细节注意事项
- 咕咕咕
参考代码
#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cctype>
#include <cmath>
#include <ctime>
#define rg register
using namespace std;
template < typename T > inline void read(T& s) {
s = 0; int f = 0; char c = getchar();
while (!isdigit(c)) f |= (c == '-'), c = getchar();
while (isdigit(c)) s = s * 10 + (c ^ 48), c = getchar();
s = f ? -s : s;
}
typedef long long LL;
const int _ = 100010;
int tot, head[_], nxt[_ << 1], ver[_ << 1];
inline void Add_edge(int u, int v)
{ nxt[++tot] = head[u], head[u] = tot, ver[tot] = v; }
int n, c[_];
int cnt, rt[_], lc[_ << 5], rc[_ << 5];
LL mx[_ << 5], col[_ << 5], ans[_];
inline void pushup(int p) {
if (mx[lc[p]] > mx[rc[p]]) mx[p] = mx[lc[p]], col[p] = col[lc[p]];
if (mx[lc[p]] < mx[rc[p]]) mx[p] = mx[rc[p]], col[p] = col[rc[p]];
if (mx[lc[p]] == mx[rc[p]]) mx[p] = mx[lc[p]], col[p] = col[lc[p]] + col[rc[p]];
}
inline void update(int& p, int x, int l = 1, int r = n) {
if (!p) p = ++cnt;
if (l == r) { ++mx[p], col[p] = l; return; }
int mid = (l + r) >> 1;
if (x <= mid) update(lc[p], x, l, mid);
else update(rc[p], x, mid + 1, r);
pushup(p);
}
inline int merge(int x, int y, int l = 1, int r = n) {
if (!x || !y) return x + y;
if (l == r)
return mx[x] += mx[y], col[x] = l, x;
int mid = (l + r) >> 1;
lc[x] = merge(lc[x], lc[y], l, mid);
rc[x] = merge(rc[x], rc[y], mid + 1, r);
return pushup(x), x;
}
inline void dfs(int u, int f) {
for (rg int i = head[u]; i; i = nxt[i]) {
int v = ver[i]; if (v == f) continue;
dfs(v, u), rt[u] = merge(rt[u], rt[v]);
}
update(rt[u], c[u]), ans[u] = col[rt[u]];
}
int main() {
#ifndef ONLINE_JUDGE
freopen("in.in", "r", stdin);
#endif
read(n);
for (rg int i = 1; i <= n; ++i) read(c[i]), rt[++cnt] = i;
for (rg int u, v, i = 1; i < n; ++i)
read(u), read(v), Add_edge(u, v), Add_edge(v, u);
dfs(1, 0);
for (rg int i = 1; i <= n; ++i) printf("%lld ", ans[i]);
return 0;
}
完结撒花 (qwq)