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Cod sursa(job #67489)
using namespace std;
#include <cstdio>
#include <vector>
#include <queue>
#include <string>
#define maxn 1<<15
#define oo 0x3f3f3f3f
struct nod { int n; int cost; nod(){}; nod(int a,int c){n=a;cost=c;};};//__attribute__((packed));
vector<vector<nod> >a;
vector<vector<int> >query;
vector<vector<int> > poz;
vector<vector<int> > sol;
int solutie[100001];
int n, m, T;
bool operator <(const nod &a, const nod &b)
{
if(a.cost>b.cost) return 1;
return 0;
}
void citire()
{
freopen("obiective.in", "r", stdin);
scanf("%d %d\n", &n, &m);
a.resize(n+1);
query.resize(n+1);
poz.resize(n+1);
sol.resize(n+1);
int p, q;
while(m--)
{
scanf("%d %d\n", &p, &q);
a[p].push_back(nod(q, 0));
a[q].push_back(nod(p, 1));
}
scanf("%d\n", &T);
for(int i=1;i<=T;++i)
{
scanf("%d %d\n",&p, &q);
query[p].push_back(q);
poz[p].push_back(i);
}
}
void dijkstra(int source)
{
priority_queue<nod> Q;
bool viz[maxn];
int d[maxn];
int nh=n, u;
Q.push(nod(source, 0));
memset(d, oo, sizeof(d));
memset(viz, 0, sizeof(viz));
d[source]=0;
vector<nod>::iterator it;
while(!Q.empty() && nh)
{
u=Q.top().n;
Q.pop();
if(viz[u]) continue;
viz[u]=1;
nh--;
for(it=a[u].begin();it!=a[u].end();++it)
if(d[it->n]>d[u]+it->cost)
{
d[it->n]=d[u]+it->cost;
Q.push(nod(it->n, d[it->n]));
}
}
vector<int>::iterator it2;
for(it2=query[source].begin();it2!=query[source].end();++it2)
sol[source].push_back(d[*it2]);
}
void solve()
{
int i;
for(i=1;i<=n;++i)
if(!query[i].empty()) dijkstra(i);
int j;
for(i=1;i<=n;++i)
for(j=0;j<query[i].size();++j)
solutie[poz[i][j]]=sol[i][j];
for(i=1;i<=T;++i) printf("%d\n", solutie[i]);
}
int main()
{
freopen("obiective.out", "w", stdout);
citire();
solve();
return 0;
}