This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
#include "catdog.h"
#define INF 0x3f3f3f3f
using namespace std;
/*
5
1 2
2 3
2 4
4 5
5
1 3
2 5
1 2
2 1
3 2
*/
/// dp[nod][c] =def= costul minim pentru a avea in componenta care-l contine pe nod doar noduri
/// colorate in c sau necolorate
/// Se observa ca pe o linie sa rezolva simplu cu un aint
/// Fac cu heavy merge-ul la dp pe chain-uri tinand in nodurile aint-ului starile celor 2 capete
/// ale chain-ului
/// Pentru muchiile light actualizez dinamica "normal" si continui pe urmatoarele chain-uri pana
/// la radacina
const int kN = 1e5;
vector<int> g[1 + kN];
int labels, sz[1 + kN], p[1 + kN], heavySon[1 + kN], chainTop[1 + kN], label[1 + kN], down[1 + kN], last[1 + kN][2], sum[1 + kN][2];
short col[1 + kN];
void minSelf(int &x, int y) {
if (y < x) {
x = y;
}
}
struct node {
int dp[2][2];
node() {
for (int i = 0; i < 2; ++i) {
for (int j = 0; j < 2; ++j) {
dp[i][j] = INF;
}
}
}
void init(int pos, int c) {
dp[0][1] = dp[1][0] = INF;
for (int i = 0; i < 2; ++i) {
if (i != c && c != 2) {
dp[i][i] = INF;
} else {
dp[i][i] = sum[pos][i];
}
}
}
node operator + (const node &rhs) const {
node ret;
for (int i = 0; i < 2; ++i) {
for (int j = 0; j < 2; ++j) {
ret.dp[i][j] = INF;
}
}
for (int a = 0; a < 2; ++a) {
for (int b = 0; b < 2; ++b) {
for (int c = 0; c < 2; ++c) {
for (int d = 0; d < 2; ++d) {
minSelf(ret.dp[a][d], dp[a][b] + rhs.dp[c][d] + (b != c));
}
}
}
}
return ret;
}
};
struct ST {
int n;
vector<node> t;
void init(int N) {
n = N;
int dim = 1;
while (dim < n) {
dim *= 2;
}
t.resize(dim * 2);
}
void build(int x, int lx, int rx) {
if (lx == rx) {
t[x].init(lx, 2);
return;
}
int mid = (lx + rx) / 2;
build(x * 2, lx, mid);
build(x * 2 + 1, mid + 1, rx);
t[x] = t[x * 2] + t[x * 2 + 1];
}
void update(int x, int lx, int rx, int pos, int c) {
if (lx == rx) {
t[x].init(pos, c);
return;
}
int mid = (lx + rx) / 2;
if (pos <= mid) {
update(x * 2, lx, mid, pos, c);
} else {
update(x * 2 + 1, mid + 1, rx, pos, c);
}
t[x] = t[x * 2] + t[x * 2 + 1];
}
void update(int pos, int c) {
update(1, 1, n, pos, c);
}
node query(int x, int lx, int rx, int st, int dr) {
if (st <= lx && rx <= dr) {
return t[x];
}
int mid = (lx + rx) / 2;
if (st <= mid && mid < dr) {
return query(x * 2, lx, mid, st, dr) + query(x * 2 + 1, mid + 1, rx, st, dr);
}
if (st <= mid) {
return query(x * 2, lx, mid, st, dr);
}
return query(x * 2 + 1, mid + 1, rx, st, dr);
}
node query(int st, int dr) {
return query(1, 1, n, st, dr);
}
} t;
void dfs1(int u) {
sz[u] = 1;
chainTop[u] = u;
for (int v : g[u]) {
if (v != p[u]) {
p[v] = u;
dfs1(v);
if (sz[heavySon[u]] < sz[v]) {
heavySon[u] = v;
}
sz[u] += sz[v];
}
}
}
void dfs2(int u) {
label[u] = ++labels;
down[chainTop[u]] = u;
if (heavySon[u] == 0) {
return;
}
chainTop[heavySon[u]] = chainTop[u];
dfs2(heavySon[u]);
for (int v : g[u]) {
if (v != p[u] && v != heavySon[u]) {
dfs2(v);
}
}
}
int getDp(node x, int i) {
int best = INF;
for (int j = 0; j < 2; ++j) {
minSelf(best, x.dp[i][j]);
minSelf(best, x.dp[i ^ 1][j] + 1);
}
return best;
}
node update(int v) {
t.update(label[v], col[v]);
int root = chainTop[v];
node chain = t.query(label[root], label[down[root]]);
if (root == 1) {
return chain;
}
for (int i = 0; i < 2; ++i) {
sum[label[p[root]]][i] -= last[root][i];
last[root][i] = getDp(chain, i);
sum[label[p[root]]][i] += last[root][i];
}
return update(p[root]);
}
void initialize(int N, vector<int> A, vector<int> B) {
for (int i = 0; i < N - 1; ++i) {
g[A[i]].emplace_back(B[i]);
g[B[i]].emplace_back(A[i]);
}
for (int v = 1; v <= N; ++v) {
col[v] = 2;
}
dfs1(1);
dfs2(1);
t.init(N);
t.build(1, 1, N);
}
int cat(int v) {
col[v] = 0;
node ret = update(v);
return min(getDp(ret, 0), getDp(ret, 1));
}
int dog(int v) {
col[v] = 1;
node ret = update(v);
return min(getDp(ret, 0), getDp(ret, 1));
}
int neighbor(int v) {
col[v] = 2;
node ret = update(v);
return min(getDp(ret, 0), getDp(ret, 1));
}
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