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| #include<stdio.h>
#include<string.h>
#include<algorithm>
#define N 10005
#define inf 0x3f3f3f3f
using namespace std;
struct node
{
int u,v,w,next;
}edge[N<<1];
int T,n,a,b,c;
char op[10];
int pre[N],cnt;
int son[N],dep[N],tid[N];
int top[N],fa[N],siz[N],id;
int maxx[N<<2];
int e[N][3];
void init()
{
cnt = id = 0;
memset(pre, -1, sizeof(pre));
memset(maxx, -inf, sizeof(maxx));
memset(siz, 0, sizeof(siz));
}
void addEdge(int u, int v, int w)
{
edge[cnt].u = u;
edge[cnt].v = v;
edge[cnt].next = pre[u];
pre[u] = cnt++;
}
void dfs1(int u, int f, int dp)
{
dep[u] = dp;
fa[u] = f;
siz[u] = 1;
son[u] = 0;
for(int i = pre[u]; ~i; i=edge[i].next)
{
int v = edge[i].v;
if(v != f)
{
dfs1(v, u, dp+1);
siz[u] += siz[v];
if(siz[v] > siz[son[u]])
son[u] = v;
}
}
}
void dfs2(int u, int tp)
{
top[u] = tp;
tid[u] = ++id;
if(son[u] == 0)return ;
dfs2(son[u], tp);
for(int i = pre[u]; ~i; i=edge[i].next)
{
int v = edge[i].v;
if(v != son[u] && v != fa[u])
dfs2(v, v);
}
}
void update(int rt, int l, int r, int pos, int w)
{
if(l == r && l == pos)
{
maxx[rt] = w;
return ;
}
int mid = (l + r) >> 1;
if(pos <= mid)
update(rt<<1, l, mid, pos, w);
else update(rt<<1|1, mid+1, r, pos, w);
maxx[rt] = max(maxx[rt<<1], maxx[rt<<1|1]);
}
int query(int rt, int l, int r, int ql, int qr)
{
if(ql <= l && r <= qr)
return maxx[rt];
int mid = (l + r) >> 1;
if(qr <= mid)
return query(rt<<1, l, mid, ql, qr);
if(ql > mid)
return query(rt<<1|1, mid+1, r, ql, qr);
return max(query(rt<<1, l, mid, ql, qr), query(rt<<1|1, mid+1, r, ql, qr));
}
int get(int x, int y)
{
int ans = -inf;
while(top[x] != top[y])
{
if(dep[top[x]] < dep[top[y]])
swap(x, y);
ans = max(ans, query(1, 2, n, tid[top[x]], tid[x]));
x = fa[top[x]];
}
if(x != y)
{
if(dep[x] > dep[y])
swap(x, y);
ans = max(ans, query(1, 2, n, tid[x]+1, tid[y]));
}
return ans;
}
void deal()
{
dfs1(1, 1, 1);
dfs2(1, 1);
for(int i = 1; i < n; ++i)
{
if(dep[e[i][0]] > dep[e[i][1]])
swap(e[i][0], e[i][1]);
update(1, 2, n, tid[e[i][1]], e[i][2]);
}
}
int main()
{
scanf("%d", &T);
while(T--)
{
init();
scanf("%d", &n);
for(int i = 1; i < n; ++i)
{
scanf("%d%d%d", &a,&b,&c);
addEdge(a, b, c);
addEdge(b, a, c);
e[i][0] = a,e[i][1] = b,e[i][2] = c;
}
deal();
while(~scanf("%s", op) && op[0]!='D')
{
scanf("%d%d", &a,&b);
if(op[0] == 'Q')
printf("%d\n", get(a, b));
else
update(1, 2, n, tid[e[a][1]], b);
}
}
return 0;
}
|
