topological sort taocp 2.2.3,vol 1

#include <iostream>
#include <vector>
#include <queue>
using namespace std;

int indegree[9];
vector<vector<int> > vv(9);
typedef vector<int>::iterator it;
queue<int> q;
bool flag[9];

void init() {
    memset(flag, false, sizeof(bool)*9);
    memset(indegree, 0, 9*sizeof(int));
    vv[0].push_back(2);++indegree[2];
    vv[1].push_back(7);++indegree[7];
    vv[2].push_back(6);++indegree[6];
    vv[3].push_back(5);++indegree[5];
    vv[4].push_back(7);++indegree[7];
    vv[6].push_back(3);++indegree[3];
    vv[6].push_back(4);++indegree[4];
    vv[7].push_back(5);++indegree[5];
    vv[8].push_back(1);++indegree[1];
    vv[8].push_back(4);++indegree[4];
}
void tsort() {
    for (int i = 0; i<=8; i++) 
        if (indegree[i] == 0 && !flag[i]) {
            q.push(i);
            while(!q.empty()) {
                int number = q.front();
                cout << number << ' ';
                flag[number]= true;
                q.pop();
                for ( it ii = vv[number].begin(); ii != vv[number].end(); ++ii) {
                    --indegree[*ii];
                    if ( indegree[*ii] == 0)
                        q.push(*ii);
                }
            }
        }
}
int main(){
    init();
    tsort();
    return 0;
}