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| #include<bits/stdc++.h>
inline int read() {
int x = 0, f = 1;
char ch = getchar();
while (ch < '0' || ch > '9') {
if (ch == '-')
f = -1;
ch = getchar();
}
while (ch >= '0' && ch <= '9')
x = x * 10 + ch - '0', ch = getchar();
return x * f;
}
using namespace std;
const int MAXN = 100005;
const int MAXM = 200005;
int n, m, q;
int edgeCount = 1;
int head[MAXN], toNode[MAXM << 1], nextEdge[MAXM << 1], fromNode[MAXM << 1];
int countDfn;
int dfn[MAXN];
int ECC;
stack<int> dfsStack;
int low[MAXN], belong[MAXN];
int newEdgeCount;
int newHead[MAXN], newToNode[MAXM << 1], newNextEdge[MAXM << 1];
int siz[MAXN], dep[MAXN], fat[MAXN];
int son[MAXN], top[MAXN];
void add(int from, int to) {
edgeCount++;
toNode[edgeCount] = to;
fromNode[edgeCount] = from;
nextEdge[edgeCount] = head[from];
head[from] = edgeCount;
return;
}
void in() {
int a, b;
n = read(), m = read();
for (int i = 1; i <= m; ++i) {
a = read(), b = read();
add(a, b), add(b, a);
}
q = read();
return;
}
void tarjan(int from, int fromEdge) {
countDfn++;
dfn[from] = low[from] = countDfn;
dfsStack.push(from);
for (int i = head[from]; i; i = nextEdge[i]) {
int to = toNode[i];
if (!dfn[to]) {
tarjan(to, i);
low[from] = min(low[from], low[to]);
} else if (i != (fromEdge ^ 1))
low[from] = min(low[from], dfn[to]);
}
if (dfn[from] == low[from]) {
ECC++;
belong[from] = ECC;
while (dfsStack.top() != from) {
belong[dfsStack.top()] = ECC;
dfsStack.pop();
}
dfsStack.pop();
}
return;
}
void newAdd(int from, int to) {
newEdgeCount++;
newToNode[newEdgeCount] = to;
newNextEdge[newEdgeCount] = newHead[from];
newHead[from] = newEdgeCount;
return;
}
void newIn() {
for (int i = 2; i <= (m << 1); i += 2) {
int from = fromNode[i], to = toNode[i];
if (belong[from] ^ belong[to]) {
newAdd(belong[from], belong[to]);
newAdd(belong[to], belong[from]);
}
}
return;
}
void dfs1(int from, int father) {
siz[from]++;
fat[from] = father;
dep[from] = dep[father] + 1;
for (int i = newHead[from]; i; i = newNextEdge[i]) {
int to = newToNode[i];
if (to != father) {
dfs1(to, from);
siz[from] += siz[to];
if (siz[son[from]] < siz[to])
son[from] = to;
}
}
return;
}
void dfs2(int from, int curTop) {
top[from] = curTop;
if (!son[from])
return;
dfs2(son[from], curTop);
for (int i = newHead[from]; i; i = newNextEdge[i]) {
int to = newToNode[i];
if (to != fat[from] && to != son[from])
dfs2(to, to);
}
return;
}
inline int lca(int a, int b) {
while (top[a] != top[b]) {
if (dep[top[a]] < dep[top[b]])
swap(a, b);
a = fat[top[a]];
}
return dep[a] < dep[b] ? a : b;
}
int main() {
int a, b, anc;
in();
tarjan(1, 0);
newIn();
dfs1(1, 0);
dfs2(1, 1);
while (q--) {
a = belong[read()], b = belong[read()];
anc = lca(a, b);
cout << dep[a] + dep[b] - (dep[anc] << 1) << '\n';
}
return 0;
}
|
