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| #include <bits/stdc++.h>
using LL = long long;
using namespace std;
const int N = 200010;
struct Node{int to,next;};
int T, n, m, q, u, v, dfn[N], clo, rev[N], f[N], semi[N], idom[N], deg[N], dep[N], fa[N][18];
struct Graph{
Node E[N << 1]; int head[N], tot;
inline void clear(){
tot = 0;
for(int i = 0; i <= n; ++i) head[i] = -1;
}
inline void link(int u, int v){
E[tot] = (Node){v, head[u]}; head[u] = tot++;
}
}pre, nxt, dom;
struct uset{
int fa[N], Mi[N];
inline void init(){
for(int i = 1; i <= n; ++i)
fa[i] = Mi[i] = semi[i] = i;
}
inline int find(int x){
if(fa[x] == x) return x;
int fx = fa[x], y = find(fa[x]);
if(dfn[semi[Mi[fx]]] < dfn[semi[Mi[x]]]) Mi[x] = Mi[fx];
return fa[x] = y;
}
}uset;
inline void tarjan(int x) {
dfn[x] = ++clo; rev[clo] = x;
for(int e = nxt.head[x]; ~e; e = nxt.E[e].next){
if(!dfn[nxt.E[e].to])
f[nxt.E[e].to] = x, tarjan(nxt.E[e].to);
}
}
inline void dfs(int x, int pre, int depth) {
dep[x] = depth;
fa[x][0] = pre;
for(int i = 1; i < 18; ++i)
fa[x][i] = fa[fa[x][i - 1]][i - 1];
for(int e = dom.head[x]; ~e; e = dom.E[e].next)
dfs(dom.E[e].to, x, depth + 1);
}
inline int LCA(int u, int v) {
if(dep[u] < dep[v]) swap(u, v);
for(int i = 17; ~i; --i) {
if(dep[fa[u][i]] >= dep[v])
u = fa[u][i];
}
if(u == v) return u;
for(int i = 17; ~i; --i) {
if(fa[u][i] != fa[v][i])
u = fa[u][i], v = fa[v][i];
}
return fa[u][0];
}
inline void calc(){
for(int i = n; i >= 2; --i){
int y = rev[i], tmp = n;
for(int e = pre.head[y]; ~e; e = pre.E[e].next){
int x = pre.E[e].to; if(!dfn[x]) continue;
if(dfn[x] < dfn[y]) tmp = min(tmp, dfn[x]);
else uset.find(x), tmp = min(tmp, dfn[semi[uset.Mi[x]]]);
}
semi[y] = rev[tmp]; uset.fa[y] = f[y];
dom.link(semi[y], y);
y = rev[i - 1];
for(int e = dom.head[y]; ~e; e = dom.E[e].next){
int x = dom.E[e].to; uset.find(x);
if(semi[uset.Mi[x]] == y) idom[x] = y;
else idom[x] = uset.Mi[x];
}
}
for(int i = 2; i <= n; ++i){
int x = rev[i];
if(idom[x] != semi[x])
idom[x] = idom[idom[x]];
}
dom.clear();
for(int i = 1; i < n; ++i)
dom.link(idom[i], i);
dfs(n, 0, 0);
}
int main() {
scanf("%d", &T);
while(T--) {
scanf("%d%d", &n, &m);
clo = 0; n++; dep[0] = -1;
for(int i = 1; i <= n; ++i)
deg[i] = dfn[i] = rev[i] = semi[i] = idom[i] = f[i] = 0;
pre.clear(); nxt.clear(); dom.clear(); uset.init();
for(int i = 1; i <= m; ++i){
scanf("%d%d", &u, &v);
pre.link(u, v);
nxt.link(v, u);
deg[u]++;
}
for(int i = 1; i < n; ++i) {
if(deg[i] == 0) {
nxt.link(n, i);
pre.link(i, n);
}
}
tarjan(n);
calc();
scanf("%d", &q);
while(q--) {
scanf("%d%d", &u, &v);
printf("%d\n", dep[u] + dep[v] - dep[LCA(u, v)]);
}
}
return 0;
}
|