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153 | #include<bits/stdc++.h>
#define up(l, r, i) for(int i = l, END##i = r;i <= END##i;++ i)
#define dn(r, l, i) for(int i = r, END##i = l;i >= END##i;-- i)
using namespace std;
typedef long long i64;
const int INF = 1e9;
const int MAXN = 1e5 + 3;
int W[MAXN];
struct Mat{ int M[2][2]; };
struct Vec{ int V[2]; };
Mat operator *(const Mat &a, const Mat &b){
Mat c;
c.M[0][0] = max(a.M[0][0] + b.M[0][0], a.M[0][1] + b.M[1][0]);
c.M[0][1] = max(a.M[0][0] + b.M[0][1], a.M[0][1] + b.M[1][1]);
c.M[1][0] = max(a.M[1][0] + b.M[0][0], a.M[1][1] + b.M[1][0]);
c.M[1][1] = max(a.M[1][0] + b.M[0][1], a.M[1][1] + b.M[1][1]);
return c;
}
Vec operator *(const Mat &a, const Vec &v){
Vec r;
r.V[0] = max(a.M[0][0] + v.V[0], a.M[0][1] + v.V[1]);
r.V[1] = max(a.M[1][0] + v.V[0], a.M[1][1] + v.V[1]);
return r;
}
namespace Gra{
vector<int> E[MAXN];
int G[MAXN], S[MAXN], D[MAXN], T[MAXN], F[MAXN];
int X[MAXN], Y[MAXN];
int H[MAXN][2];
int K[MAXN][2];
struct Mat M[MAXN];
void dfs1(int u, int f){
S[u] = 1;
F[u] = f;
for(auto &v : E[u]) if(v != f){
dfs1(v, u);
S[u] += S[v];
if(S[v] > S[G[u]]) G[u] = v;
}
}
int o;
void dfs2(int u, int f){
if(u == G[f])
X[u] = X[f];
else
X[u] = u;
H[u][0] = H[u][1] = 0;
K[u][0] = K[u][1] = 0;
const int &g = G[u];
D[u] = ++ o;
T[o] = u;
if(g){
dfs2(g, u);
Y[u] = Y[g];
K[u][0] += max(K[g][0], K[g][1]);
K[u][1] += K[g][0];
} else {
Y[u] = u;
}
for(auto &v : E[u]) if(v != f && v != g){
dfs2(v, u);
H[u][0] += max(K[v][0], K[v][1]);
H[u][1] += K[v][0];
}
M[u].M[0][0] = H[u][0];
M[u].M[0][1] = H[u][0];
M[u].M[1][0] = H[u][1] + W[u];
M[u].M[1][1] = -INF;
K[u][0] += H[u][0];
K[u][1] += H[u][1] + W[u];
}
}
namespace Seg{
const int SIZ = 4e5 + 3;
struct Mat M[SIZ];
#define lc(t) (t << 1)
#define rc(t) (t << 1 | 1)
void pushup(int t, int a, int b){
M[t] = M[lc(t)] * M[rc(t)];
}
void build(int t, int a, int b){
if(a == b){
M[t] = Gra :: M[Gra :: T[a]];
} else {
int c = a + b >> 1;
build(lc(t), a, c);
build(rc(t), c + 1, b);
pushup(t, a, b);
}
}
void modify(int t, int a, int b, int p, const Mat &w){
if(a == b){
M[t] = w;
} else {
int c = a + b >> 1;
if(p <= c) modify(lc(t), a, c, p, w);
else modify(rc(t), c + 1, b, p, w);
pushup(t, a, b);
}
}
Mat query(int t, int a, int b, int l, int r){
if(l <= a && b <= r){
return M[t];
} else {
int c = a + b >> 1;
if(r <= c) return query(lc(t), a, c , l, r); else
if(l > c) return query(rc(t), c + 1, b, l, r); else
return query(lc(t), a, c , l, r) *
query(rc(t), c + 1, b, l, r);
}
}
}
int qread();
int main(){
int n = qread(), m = qread();
up(1, n, i)
W[i] = qread();
up(2, n, i){
int u = qread(), v = qread();
Gra :: E[u].push_back(v);
Gra :: E[v].push_back(u);
}
Gra :: dfs1(1, 0);
Gra :: dfs2(1, 0);
Seg :: build(1, 1, n);
Vec v0;
v0.V[0] = v0.V[1] = 0;
up(1, m, i){
using namespace Gra;
int x = qread(), y = qread();
W[x] = y;
int u = x;
while(u != 0){
const int &v = X[u];
const int &f = F[v];
M[u].M[0][0] = H[u][0];
M[u].M[0][1] = H[u][0];
M[u].M[1][0] = H[u][1] + W[u];
M[u].M[1][1] = -INF;
const Vec p = Seg :: query(1, 1, n, D[v], D[Y[u]]) * v0;
Seg :: modify(1, 1, n, D[u], M[u]);
const Vec q = Seg :: query(1, 1, n, D[v], D[Y[u]]) * v0;
if(f != 0){
H[f][0] = H[f][0] - max(p.V[0], p.V[1]) + max(q.V[0], q.V[1]);
H[f][1] = H[f][1] - p.V[0] + q.V[0];
}
u = f;
}
Vec v1 = Seg :: query(1, 1, n, D[1], D[Y[1]]) * v0;
printf("%d\n", max(v1.V[0], v1.V[1]));
}
return 0;
}
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