【SPOJ】6779 Can you answer these queries VII

#include<cstdio>
#include<cstring>
#include<queue>
#include<iostream>
#define MAX(a,b) ((a)>(b)?(a):(b))
#define oo 0x7FFFFFFF
#define MAXN 200010
using namespace std;
bool vis[MAXN];
int e, first[MAXN], next[MAXN], v[MAXN];
struct LCT {
int bef[MAXN];
int next[MAXN][2], pre[MAXN], key[MAXN], num[MAXN];
int left[MAXN], right[MAXN], sum[MAXN], val[MAXN], same[MAXN];
inline void PushUp(int x) {
int L, R;
L = next[x][0], R = next[x][1];
num[x] = num[L] + num[R] + 1;
sum[x] = sum[L] + sum[R] + key[x];
left[x] = MAX(left[L],sum[L]+key[x]+left[R]);
right[x] = MAX(right[R],sum[R]+key[x]+right[L]);
val[x] = MAX(val[L],val[R]);
val[x] = MAX(val[x],key[x]+right[L]+left[R]);
}
inline void Down(int x, int k) {
if (x) {
same[x] = key[x] = k;
sum[x] = k * num[x];
left[x] = right[x] = val[x] = MAX(sum[x],0);
}
}
inline void PushDown(int x) {
if (same[x] != oo) {
int L, R;
L = next[x][0], R = next[x][1];
if (L) {
same[L] = key[L] = same[x];
sum[L] = same[x] * num[L];
left[L] = right[L] = val[L] = MAX(sum[L],0);
}
if (R) {
same[R] = key[R] = same[x];
sum[R] = same[x] * num[R];
left[R] = right[R] = val[R] = MAX(sum[R],0);
}
same[x] = oo;
}
}
void Rotate(int x, int kind) {
int y, z;
y = pre[x];
z = pre[y];
PushDown(y);
PushDown(x);
next[y][!kind] = next[x][kind];
pre[next[x][kind]] = y;
next[z][next[z][1] == y] = x;
pre[x] = z;
next[x][kind] = y;
pre[y] = x;
PushUp(y);
}
void Splay(int x) {
int rt;
for (rt = x; pre[rt]; rt = pre[rt])
;
if (rt != x) {
bef[x] = bef[rt];
bef[rt] = 0;
while (pre[x]) {
if (next[pre[x]][0] == x)
Rotate(x, 1);
else
Rotate(x, 0);
}
PushUp(x);
} else
PushDown(x);
}
void Access(int x) {
int father;
for (father = 0; x; x = bef[x]) {
Splay(x);
bef[next[x][1]] = x;
pre[next[x][1]] = 0;
next[x][1] = father;
pre[father] = x;
bef[father] = 0;
father = x;
PushUp(x);
}
}
int Query(int x, int y) {
int ans;
Access(y);
for (y = 0; x; x = bef[x]) {
Splay(x);
if (!bef[x]) {
ans = MAX(val[y],val[next[x][1]]);
ans = MAX(ans,key[x]+left[y]+left[next[x][1]]);
return ans;
}
bef[next[x][1]] = x;
pre[next[x][1]] = 0;
next[x][1] = y;
pre[y] = x;
bef[y] = 0;
y = x;
PushUp(x);
}
return 0;
}
void Update(int x, int y, int price) {
Access(y);
for (y = 0; x; x = bef[x]) {
Splay(x);
if (!bef[x]) {
key[x] = price;
if (y) {
same[y] = key[y] = price;
sum[y] = price * num[y];
left[y] = right[y] = val[y] = MAX(price,0);
}
if (next[x][1]) {
y = next[x][1];
same[y] = key[y] = price;
sum[y] = price * num[y];
left[y] = right[y] = val[y] = MAX(price,0);
}
}
bef[next[x][1]] = x;
pre[next[x][1]] = 0;
next[x][1] = y;
pre[y] = x;
bef[y] = 0;
y = x;
PushUp(x);
}
}
} lct;
inline void AddEdge(int x, int y) {
v[e] = y;
next[e] = first[x];
first[x] = e++;
}
void BFS(int x) {
int i, y;
queue<int> q;
vis[x] = true;
q.push(x);
while (!q.empty()) {
x = q.front();
q.pop();
for (i = first[x]; i != -1; i = next[i]) {
y = v[i];
if (!vis[y]) {
lct.same[y] = oo;
lct.bef[y] = x;
vis[y] = true;
q.push(y);
}
}
}
}
int INT() {
int res;
char ch;
bool neg;
while (ch = getchar_unlocked(), !isdigit(ch) && ch != '-')
;
if (ch == '-') {
res = 0;
neg = true;
} else {
res = ch - '0';
neg = false;
}
while (ch = getchar_unlocked(), isdigit(ch))
res = res * 10 + ch - '0';
return neg ? -res : res;
}
int main() {
int n, i, q, cmd, x, y, val;
n = INT();
for (i = 1; i <= n; i++) {
lct.key[i] = INT();
lct.same[i] = oo;
}
memset(first, -1, sizeof(first));
for (e = 0, i = 1; i < n; i++) {
x = INT(), y = INT();
AddEdge(x, y);
AddEdge(y, x);
}
BFS(1);
scanf("%d", &q);
while (q--) {
cmd = INT(), x = INT(), y = INT();
if (cmd == 1)
printf("%d\n", lct.Query(x, y));
else {
val = INT();
lct.Update(x, y, val);
}
}
return 0;
}