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| #include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5, inf = 0x3f3f3f3f;
int n, m, q;
int low[N], dfn[N], stk[N], clk, top, cnt;
int val[N];
vector<int> G[N], T[N<<1];
void tarjan(int u, int fa)
{
low[u] = dfn[u] = ++clk;
stk[++top] = u;
for(int v : G[u])
{
if(!dfn[v])
{
tarjan(v, u);
low[u] = min(low[u], low[v]);
if(low[v]>=dfn[u])
{
++cnt;
for(int x=0; x!=v; top--)
{
x = stk[top];
T[cnt].push_back(x);
T[x].push_back(cnt);
}
T[cnt].push_back(u);
T[u].push_back(cnt);
}
}
else if(v!=fa) low[u] = min(low[u], dfn[v]);
}
}
const int M = N<<1;
multiset<int> mst[M];
namespace HLD
{
int sz[M], top[M], son[M], dep[M], fa[M], dfn[M], idfn[M], tot;
void dfs1(int u, int f)
{
dep[u] = dep[f] + 1; fa[u] = f;
sz[u] = 1;
if(u<=n) mst[u].insert(val[u]);
for(int v : T[u])
{
if(v!=f)
{
if(u>n) mst[u].insert(val[v]);
dfs1(v, u);
sz[u] += sz[v];
if(sz[v]>sz[son[u]]) son[u] = v;
}
}
}
void dfs2(int u, int t)
{
top[u] = t;
dfn[u] = ++tot;
idfn[tot] = u;
if(!son[u]) return;
dfs2(son[u], t);
for(int v : T[u])
if(v!=son[u]&&v!=fa[u]) dfs2(v, v);
}
}
using HLD::fa;
using HLD::idfn;
using HLD::dep;
struct seg
{
int l, r, mn;
}t[M<<2];
void pull(int p) { t[p].mn = min(t[p<<1].mn, t[p<<1|1].mn); }
void build(int p, int l, int r)
{
t[p].l = l, t[p].r = r;
if(l==r)
{
t[p].mn = *mst[idfn[l]].begin();
return;
}
int mid = (l+r)>>1;
build(p<<1, l, mid); build(p<<1|1, mid+1, r);
pull(p);
}
void upd(int p, int x, int y)
{
int l = t[p].l, r = t[p].r;
if(l==r)
{
t[p].mn = y;
return;
}
int mid = (l+r)>>1;
if(x<=mid) upd(p<<1, x, y);
else upd(p<<1|1, x, y);
pull(p);
}
int ask(int p, int x, int y)
{
int l = t[p].l, r = t[p].r;
if(l>=x && r<=y) return t[p].mn;
int mid = (l+r)>>1, ans = inf;
if(x<=mid) ans = min(ans, ask(p<<1, x, y));
if(y>mid) ans = min(ans, ask(p<<1|1, x, y));
return ans;
}
int askt(int x, int y)
{
int ans = inf;
while(HLD::top[x]!=HLD::top[y])
{
if(dep[HLD::top[x]]<dep[HLD::top[y]]) swap(x,y);
ans = min(ans, ask(1, HLD::dfn[HLD::top[x]], HLD::dfn[x]));
x = fa[HLD::top[x]];
}
if(dep[x]>dep[y]) swap(x,y);
ans = min(ans, ask(1, HLD::dfn[x], HLD::dfn[y]));
if(x>n) ans = min(ans, val[fa[x]]);
return ans;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m >> q;
for(int i=1; i<=n; i++) cin >> val[i];
for(int i=1; i<=m; i++)
{
int u, v; cin >> u >> v;
G[u].push_back(v); G[v].push_back(u);
}
cnt = n; tarjan(1, 0);
HLD::dfs1(1, 0), HLD::dfs2(1, 1);
build(1, 1, 2*n);
while(q--)
{
char op; int x, y;
cin >> op >> x >> y;
if(op=='C')
{
if(fa[x])
{
int pre = *mst[fa[x]].begin();
mst[fa[x]].erase(mst[fa[x]].find(val[x]));
mst[fa[x]].insert(y);
int cur = *mst[fa[x]].begin();
if(pre!=cur) upd(1, HLD::dfn[fa[x]], cur);
}
val[x] = y;
upd(1, HLD::dfn[x], y);
}
else cout << askt(x, y) << '\n';
}
return 0;
}
|