关键路径-STL版

给定有向图无环的边信息，求每个顶点的最早开始时间、最迟开始时间。

// 参考代码

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

class Vertex {
public:
    int indexNo;
    bool hasEnterQueue;
    int early;
    int later;

    Vertex(int indexNo) {
        this->indexNo = indexNo;
        this->hasEnterQueue = false;
        early = -1;
        later = 0x7FFFF;
    }
    void updateEarly(int parentEarly, int edgeValue) {
        int newEarly = parentEarly + edgeValue;
        if (newEarly > this->early)
            this->early = newEarly;
    }
    void updateLater(int childLater, int edgeValue) {
        int newLater = childLater - edgeValue;
        if (newLater < this->later)
            this->later = newLater;
    }
};


class Graph {
public:
    vector<Vertex> vertexes;
    vector<vector<int> > adjMat;
    int n;
public:
    void readVertexes() {
        //TODO: 将顶点数读入成员变量n
        
        //TODO： 从输入初始化vertexes数组
        int i=0;
        for(; i<n; ++i) {
            Vertex v(i);
            this->vertexes.push_back(v);
        }
        
        //为成员变量adjMat创建内存，赋初值
        for(i=0; i<n; ++i) {
            vector<int> row;
            int j=0;
            for(; j<n; ++j) {
                //TODO： 将0增加到row最后
            }
           //TODO： 将row增加到adjMat最后
        }
    }
    void readAdjMatrix() {
        //read the adjacent info into this->adjMat
        int edges;
        cin >> edges;
        int i=0;
        int s, t, w;  //s源顶点编号，t目的顶点编号，w边长
        for(; i<edges; ++i) {
            //TODO: 读入s,t,w，并将adjMat的第s行、第t列的值改为w.
        }
    }

    void updateEarly(int parentNo, queue<int>& earlyQue) {
        int parentEarly = vertexes[parentNo].early;  //读入父结点early值

        int j=0;
        for(; j<n; ++j) {
            int edgeValue = adjMat[parentNo][j];
            if (edgeValue == 0) continue;  //若父结点与结点j没有边相连，pass

            Vertex& child = vertexes[j];
            child.updateEarly(parentEarly, edgeValue); //更新子结点j的early信息

            if(!child.hasEnterQueue) {
                child.hasEnterQueue = true; //将子结点加入队列
                earlyQue.push(j);
            }
        }
    }
    void updateLater(int childNo, queue<int>& laterQue) {
        //TODO:
    }

    int getRoot() {
        //获取入度为0的顶点
        int j=0;
        for(; j<n; ++j) {
            int i=0;
            for(; i<n && adjMat[i][j] == 0; ++i);
            if (i>=n) return j; //j has not any in-edges.
        }
        return -1;  //表示没找到
    }
    int getLeaf() {
        //TODO： 获取出度为0的顶点
    }

    void printEarlyLater(bool isEarly) {
        int i=0;
        for(; i<n; ++i) {
            Vertex& v = vertexes[i];
            if (isEarly)
                cout << v.early << " ";
            else {
                cout << v.later << " ";
            }
        }
        cout << endl;
    }

    void findEarly() {
        //执行关键路径算法，求每个顶点的最早开始时间。
        int r = getRoot();
        Vertex& root = vertexes[r];
        root.hasEnterQueue = true;
        root.early = 0;

        queue<int> que;
        que.push(r);

        while(!que.empty()) {
            int p = que.front();
            que.pop();

            updateEarly(p, que);
        }

        printEarlyLater(true);
    }
    void clearEnterQueue() {
        int i=0;
        for(; i<n; ++i) {
            vertexes[i].hasEnterQueue = false;
        }
    }
    void findLater() {
        //TODO：调用clearEnterQueue，以清除每个顶点的hasEnterQueue=false
        //执行关键路径算法，求每个顶点的最迟开始时间。
    }

    void main() {
        readVertexes();
        readAdjMatrix();
        findEarly();
        findLater();
    }
};


int main() {
    int t=1;
    //cin >> t;
    while (t--) {
        Graph g;
        g.main();
    }
    return 0;
}