POJ 3237 Tree

#include<stdio.h>
#include<string.h>
#define MAXD 100010
#define MAXM 200010
#define INF 0x7fffffff
int N, q[MAXD], first[MAXD], e, next[MAXM], v[MAXM], w[MAXM], dep[MAXD];
struct Edge
{
int x, y, z;
}edge[MAXD];
struct Splay
{
int pre, ls, rs, neg, key, max, min;
bool root;
void update(); void pushdown(); void zig(int ); void zag(int ); void splay(int );
void renew()
{
root = true;
pre = ls = rs = 0;
neg = 0;
}
}sp[MAXD];
int Max(int x, int y)
{
return x > y ? x : y;
}
int Min(int x, int y)
{
return x < y ? x : y;
}
void Splay::update()
{
max = Max(Max(sp[ls].max, sp[rs].max), key);
min = Min(Min(sp[ls].min, sp[rs].min), key);
}
void makeneg(int cur)
{
if(cur != 0)
{
sp[cur].neg ^= 1, sp[cur].key = -sp[cur].key;
int t = sp[cur].max;
sp[cur].max = -sp[cur].min, sp[cur].min = -t;
}
}
void Splay::pushdown()
{
if(neg)
{
makeneg(ls), makeneg(rs);
neg = 0;
}
}
void Splay::zig(int x)
{
int y = rs, fa = pre;
pushdown(), sp[y].pushdown();
rs = sp[y].ls, sp[rs].pre = x;
sp[y].ls = x, pre = y;
sp[y].pre = fa;
if(root)
root = false, sp[y].root = true;
else
sp[fa].rs == x ? sp[fa].rs = y : sp[fa].ls = y;
update();
}
void Splay::zag(int x)
{
int y = ls, fa = pre;
pushdown(), sp[y].pushdown();
ls = sp[y].rs, sp[ls].pre = x;
sp[y].rs = x, pre = y;
sp[y].pre = fa;
if(root)
root = false, sp[y].root = true;
else
sp[fa].rs == x ? sp[fa].rs = y : sp[fa].ls = y;
update();
}
void Splay::splay(int x)
{
int y, z;
for(pushdown(); !root;)
{
y = pre;
if(sp[y].root)
sp[y].rs == x ? sp[y].zig(y) : sp[y].zag(y);
else
{
z = sp[y].pre;
if(sp[z].rs == y)
{
if(sp[y].rs == x)
sp[z].zig(z), sp[y].zig(y);
else
sp[y].zag(y), sp[z].zig(z);
}
else
{
if(sp[y].ls == x)
sp[z].zag(z), sp[y].zag(y);
else
sp[y].zig(y), sp[z].zag(z);
}
}
}
update();
}
void add(int x, int y, int z)
{
v[e] = y, w[e] = z;
next[e] = first[x], first[x] = e ++;
}
void prepare()
{
int i, j, x, rear = 0;
sp[0].max = -INF, sp[0].min = INF;
q[rear ++] = 1;
sp[1].renew(), dep[1] = 1;
for(i = 0; i < rear; i ++)
{
x = q[i];
for(j = first[x]; j != -1; j = next[j])
if(v[j] != sp[x].pre)
{
sp[v[j]].renew(), sp[v[j]].pre = x, dep[v[j]] = dep[x] + 1;
sp[v[j]].key = sp[v[j]].max = sp[v[j]].min = w[j];
q[rear ++] = v[j];
}
}
}
void Swap(int &x, int &y)
{
int t;
t = x, x = y, y = t;
}
void init()
{
int i;
memset(first, -1, sizeof(first));
e = 0;
scanf("%d", &N);
for(i = 1; i < N; i ++)
{
scanf("%d%d%d", &edge[i].x, &edge[i].y, &edge[i].z);
add(edge[i].x, edge[i].y, edge[i].z), add(edge[i].y, edge[i].x, edge[i].z);
}
prepare();
for(i = 1; i < N; i ++)
if(dep[edge[i].x] > dep[edge[i].y])
Swap(edge[i].x, edge[i].y);
}
void access(int x)
{
int fx;
for(fx = x, x = 0; fx != 0; x = fx, fx = sp[x].pre)
{
sp[fx].splay(fx);
sp[sp[fx].rs].root = true;
sp[fx].rs = x, sp[x].root = false;
sp[fx].update();
}
}
void Change(int x, int y)
{
sp[x].splay(x);
sp[x].key = y;
sp[x].update();
}
void Negate(int x, int y)
{
int fy;
access(x);
for(fy = y, y = 0; fy != 0; y = fy, fy = sp[y].pre)
{
sp[fy].splay(fy);
if(sp[fy].pre == 0)
makeneg(sp[fy].rs), makeneg(y);
sp[sp[fy].rs].root = true;
sp[fy].rs = y, sp[y].root = false;
sp[fy].update();
}
}
void Query(int x, int y)
{
int fy;
access(x);
for(fy = y, y = 0; fy != 0; y = fy, fy = sp[y].pre)
{
sp[fy].splay(fy);
if(sp[fy].pre == 0)
printf("%d\n", Max(sp[sp[fy].rs].max, sp[y].max));
sp[sp[fy].rs].root = true;
sp[fy].rs = y, sp[y].root = false;
sp[fy].update();
}
}
void solve()
{
int x, y;
char op[10];
for(;;)
{
scanf("%s", op);
if(op[0] == 'D')
break;
scanf("%d%d", &x, &y);
if(op[0] == 'C')
Change(edge[x].y, y);
else if(op[0] == 'N')
Negate(x, y);
else
Query(x, y);
}
}
int main()
{
int t;
scanf("%d", &t);
while(t --)
{
init();
solve();
}
return 0;
}