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Cod sursa(job #981154)
#include<stdio.h>
#include<queue>
#define NMAX 100001
using namespace std;
int vis[NMAX], d[NMAX];
struct Node{
int value;
struct Node *next;
};
int N, M, S;
struct Node *L[NMAX];
void read(FILE *pf){
struct Node *p;
int i, u, v;
fscanf(pf, "%d %d %d", &N, &M, &S);
for(i = 1; i <= N; i++){
d[i] = 0;
vis[i] = 0;
}
for(i = 1; i <= M; i++){
fscanf(pf, "%d %d", &u, &v);
p = new Node;
p->value = v;
p->next = L[u];
L[u] = p;
}
}
void BFS(int S){
struct Node *p;
int u, v;
queue<int> Q;
Q.push(S);
vis[S] = 1;
while(!Q.empty()){
u = Q.front();
Q.pop();
p = L[u];
while(p != NULL){
v = p->value;
if(vis[v] == 0){
Q.push(v);
d[v] = d[u] + 1;
vis[v] = 1;
}
p = p->next;
}
}
}
void print(FILE *pg){
int i;
for(i = 1; i <= N; i++){
if(d[i] == 0 && i != S)
d[i] = -1;
fprintf(pg, "%d ", d[i]);
}
}
int main(){
FILE *pf, *pg;
pf = fopen("bfs.in", "r");
pg = fopen("bfs.out", "w");
read(pf);
BFS(S);
print(pg);
fclose(pf);
fclose(pg);
return 0;
}