poj 2367拓扑排序

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Source Code

Problem: 2367 User: fan1913068672Memory: 276K Time: 16MSLanguage: C++ Result: Accepted

Source Code

#include"iostream"#include"stack"#include"vector"#include"cstdio"using namespace std;vector< vector<int> > G;//采用邻接表保存图vector<int> degree;     //度数表vector<int> is_in_stack;//判断是否入过栈vector<int> ans;        //保存答案int n,m;                //点数 弧数int topo_sort(){    stack<int> st;    for(int i=1;i<=n;i++){  //先找到入度为0的点 压入栈中        if(degree[i]==0){            st.push(i);            is_in_stack[i] = 1; //更新点的标志        }    }    while(!st.empty()){        int now = st.top();st.pop();        ans.push_back(now);        for(int i=0;i<G[now].size();i++){//把邻接的点的度数更新            degree[G[now][i]]--;        }        for(int i=1;i<=n;i++){            if(degree[i]==0&&!is_in_stack[i]){//把更新之后的图中入度为0的点入栈                st.push(i);                is_in_stack[i]=1;            }        }    }}int main(){    while(cin>>n){        G.resize(n+1);        is_in_stack.resize(n+1);        degree.resize(n+1);        for(int i=1;i<=n;i++){            int ed;            while(scanf("%d",&ed)&&ed){                G[i].push_back(ed);            }        }        for(int i=1;i<=n;i++){            is_in_stack[i]=0;            for(int j=0;j<G[i].size();j++){                degree[G[i][j]]++;            }        }        topo_sort();        int first = 1;        for(int i=0;i<ans.size();i++){            if(first) {first = 0;cout<<ans[i];}            //else cout<<"--->"<<ans[i];            else cout<<" "<<ans[i];        }        cout<<endl;    }    return 0;}

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