1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
| #include <cstdio>
#include <set>
#include <vector>
#define pb push_back
using namespace std;
template <class Type>
void read (Type &x)
{
char c;
bool flag = false;
while ((c = getchar()) < '0' || c > '9')
c == '-' && (flag = true);
x = c - '0';
while ((c = getchar()) >= '0' && c <= '9')
x = (x << 1) + (x << 3) + c - '0';
flag && (x = ~x + 1);
}
template <class Type, class ...rest>
void read (Type &x, rest &...y) { read(x), read(y...); }
template <class Type>
void write (Type x)
{
x < 0 && (putchar('-'), x = ~x + 1);
x > 9 && (write(x / 10), 0);
putchar('0' + x % 10);
}
typedef long long LL;
const int N = 2e5 + 10, inf = 1e9;
int top, stk[N];
int stmp, dfn[N], low[N];
int n, m, q, tot, p[N], w[N];
multiset <int> s[N];
vector <int> g[N], e[N];
namespace TreeSplit
{
int mn[N << 2];
int d[N], sz[N], son[N];
int stmp, top[N], dfn[N], rnk[N];
void dfs1 (int u = 1)
{
sz[u] = 1;
for (int v : e[u]) if (v ^ p[u])
{
p[v] = u;
d[v] = d[u] + 1;
dfs1(v);
sz[u] += sz[v];
if (sz[v] > sz[son[u]]) son[u] = v;
}
}
void dfs2 (int u = 1, int t = 1)
{
rnk[dfn[u] = ++stmp] = u;
top[u] = t;
if (!son[u]) return;
dfs2(son[u], t);
for (int v : e[u])
if (v ^ p[u] && v ^ son[u]) dfs2(v, v);
}
void pushup (int x) { mn[x] = min(mn[x << 1], mn[x << 1 | 1]); }
void build (int L = 1, int R = tot, int x = 1)
{
if (L == R) return void(mn[x] = w[rnk[L]]);
int mid = L + R >> 1;
build(L, mid, x << 1), build(mid + 1, R, x << 1 | 1);
pushup(x);
}
void modify (int t, int k, int L = 1, int R = tot, int x = 1)
{
if (L == R) return void(mn[x] = k);
int mid = L + R >> 1;
t <= mid ? modify(t, k, L, mid, x << 1) : modify(t, k, mid + 1, R, x << 1 | 1);
pushup(x);
}
int query (int l, int r, int L = 1, int R = tot, int x = 1)
{
if (l > R || L > r) return inf;
if (L >= l && R <= r) return mn[x];
int mid = L + R >> 1;
return min(query(l, r, L, mid, x << 1), query(l, r, mid + 1, R, x << 1 | 1));
}
int QueryPath (int a, int b)
{
int res = inf;
while (top[a] ^ top[b])
{
if (d[top[a]] < d[top[b]]) swap(a, b);
res = min(res, query(dfn[top[a]], dfn[a]));
a = p[top[a]];
}
if (d[a] > d[b]) swap(a, b);
res = min(res, query(dfn[a], dfn[b]));
if (a > n) res = min(res, w[p[a]]);
return res;
}
}
void tarjan (int u)
{
stk[++top] = u;
low[u] = dfn[u] = ++stmp;
for (int v : g[u])
if (!dfn[v])
{
tarjan(v);
low[u] = min(low[u], low[v]);
if (low[v] == dfn[u])
{
w[++tot] = 0;
int x;
do
{
x = stk[top--];
e[tot].pb(x), e[x].pb(tot);
++w[tot];
} while (x ^ v);
e[tot].pb(u), e[u].pb(tot), ++w[tot];
}
}
else low[u] = min(low[u], dfn[v]);
}
int main ()
{
read(n, m, q);
for (int i = 1; i <= n; ++i) read(w[i]);
for (int a, b; m; --m)
read(a, b), g[a].pb(b), g[b].pb(a);
tot = n;
tarjan(1);
TreeSplit::dfs1(), TreeSplit::dfs2();
for (int i = 1; i <= n; ++i)
if (p[i]) s[p[i]].insert(w[i]);
for (int i = n + 1; i <= tot; ++i)
w[i] = *s[i].begin();
TreeSplit::build();
for (char op[3]; q; --q)
{
scanf("%s", op);
if (*op == 'C')
{
int a, b; read(a, b);
TreeSplit::modify(TreeSplit::dfn[a], b);
if (p[a])
{
int c = p[a];
s[c].erase(w[a]), s[c].insert(b);
if (w[c] ^ *s[c].begin())
TreeSplit::modify(TreeSplit::dfn[c], w[c] = *s[c].begin());
}
w[a] = b;
}
else
{
int a, b; read(a, b);
write(TreeSplit::QueryPath(a, b)), puts("");
}
}
return 0;
}
|