终于AC了“最短路径”

时间：2015-12-07 16:04:45 阅读：203 评论：0 收藏：0 [点我收藏+]

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今天做了一道关于最短路径的算法题，虽然最后AC了，但是我写的第一个算法，我认为是没有问题的，自己编写的测试用例也全部通过，反复调试了，都没有错误。可是在OJ上一提交就提示Wrong Answer，真是苦闷啊！希望看到这篇文章的同志们给些提示。

两个算法都是用邻接表存储图的，都是比较纯粹的自定义结构体，使用的是DijkStra算法。虽然用容器也可以实现邻接表，但是个人感觉用结构体是比较简单，可以不用了解底层的实现。但是本人就是喜欢钻研一些基础的东西，无它，兴趣使然。

题目描述：: 给你n个点，m条无向边，每条边都有长度d和花费p，给你起点s终点t，要求输出起点到终点的最短距离及其花费，如果最短距离有多条路线，则输出花费最少的。

输入：: 输入n,m，点的编号是1~n,然后是m行，每行4个数 a,b,d,p，表示a和b之间有一条边，且其长度为d，花费为p。最后一行是两个数 s,t;起点s，终点t。n和m为0时输入结束。
(1<n<=1000, 0<m<100000, s != t)

输出：: 输出一行有两个数，最短距离及其花费。

样例输入：

样例输出：

9 11

第一个算法---为啥子错撒？

#include <iostream>
#include <malloc.h>
#define MAXVALUE 999999;
#define MAX_VERTEX_NUM 1001
#define MAX_EDGE_NUM 100001
using namespace std;
 
struct ArcNode{
    int vertex;
    int len;
    int cost;
    ArcNode *nextarc;
};
 
typedef struct VertexNode{
    ArcNode *firstArc;
    int size;
}VNode[MAX_VERTEX_NUM];
 
struct Graph{
    VNode nodes;
    int n, e;
};
int dist[MAX_VERTEX_NUM];
int cost[MAX_VERTEX_NUM];
bool visited[MAX_VERTEX_NUM];
//Edge edges[MAX_EDGE_NUM];
void allocateArcNode(ArcNode** arcNode)
{
    *arcNode = (ArcNode*)malloc(sizeof(ArcNode));
    (*arcNode)->nextarc = NULL;
}
 
void initeGraph(Graph &graph)
{
    for (int i = 1; i <= MAX_VERTEX_NUM; i++)
    {
        graph.nodes[i].firstArc = NULL;
        graph.nodes[i].size = 0;
    }
 
    graph.n = 0;
    graph.e = 0;
}
 
void createGraph(Graph &graph, int m)
{
    int v1, v2, len, cost;
    ArcNode* p1 = NULL;
    ArcNode* p2 = NULL;
    for (int i = 1; i <= m; i++)
    {
        allocateArcNode(&p1);
        allocateArcNode(&p2);
        cin >> v1 >> v2 >> len >> cost;
        p1->vertex = v2;
        p1->len = len;
        p1->cost = cost;
        p1->nextarc = graph.nodes[v1].firstArc;
        graph.nodes[v1].firstArc = p1;
        graph.nodes[v1].size++;
        p2->vertex = v1;
        p2->len = len;
        p2->cost = cost;
        p2->nextarc = graph.nodes[v2].firstArc;
        graph.nodes[v2].firstArc = p2;
        graph.nodes[v2].size++;
    }
}
 
//void printGraph(const Graph& graph, int n)
//{
//  for (int i = 1; i <= n; i++)
//  {
//      ArcNode* arcPtr = graph.nodes[i].firstArc;
//
//      cout << i << ":    ";
//      cout << "size:" << graph.nodes[i].size << endl;
//      while (arcPtr != NULL)
//      {
//          cout << arcPtr->len << ‘ ‘ << arcPtr->cost << ";";
//          arcPtr = arcPtr->nextarc;
//      }
//
//      cout << endl;
//  }
//}
 
void dijkStra(const Graph &graph, int v0, int n)
{
    int index = v0;
    for (int i = 1; i <= n; i++)
    {
        ArcNode *arcPtr = graph.nodes[index].firstArc;
        while (arcPtr != NULL)
        {
            int tmp = arcPtr->vertex;
            int len = arcPtr->len;
            int co = arcPtr->cost;
            if (visited[tmp] == false || dist[tmp] > dist[index] + len || (dist[tmp] == dist[index] + len && cost[tmp] > cost[index] + co))
            {
                dist[tmp] = arcPtr->len;
                cost[tmp] = arcPtr->cost;
            }
            arcPtr = arcPtr->nextarc;
        }
        int minLen = MAXVALUE;
        int minCost = MAXVALUE;
        for (int j = 1; j <= n; j++)
        {
            if (visited[j] == false && (dist[j] < minLen || (dist[j] == minLen && cost[j] < minCost)))
            {
                minLen = dist[j];
                index = j;
            }
        }
        visited[index] = true;
    }
}
 
void freeSpaceOfGraph(Graph& graph)
{
    for (int i = 1; i <= graph.n; i++)
    {
        ArcNode *arcPtr = graph.nodes[i].firstArc;
        while (arcPtr != NULL)
        {
            ArcNode *tmp = arcPtr;
            arcPtr = arcPtr->nextarc;
            delete tmp;
        }
    }
}
 
int main()
{
    int n, m;
 
    while (cin >> n >> m)
    {
        if (n == 0 && m == 0)
            break;
        int start, end;
 
        for (int i = 1; i <= n; i++)
        {
            visited[i] = false;
            cost[i] = MAXVALUE;
            dist[i] = MAXVALUE;
        }
 
        Graph graph;
        initeGraph(graph);
        graph.n = n;
        graph.e = m;
        createGraph(graph, m);
        cin >> start >> end;
        dijkStra(graph, start, n);
        cout << dist[end] << ‘ ‘ << cost[end] << endl;
        freeSpaceOfGraph(graph);
    }
    return 0;
}

View Code

第二算法---完美AC

#include <iostream>
#include <malloc.h>
#define MAXVALUE 123123123
#define MAX_VERTEX_NUM 1001
#define MAX_EDGE_NUM 100001
using namespace std;
 
struct ArcNode{
    int vertex;
    int len;
    int cost;
    ArcNode *nextarc;
};
 
typedef struct VertexNode{
    ArcNode *firstArc;
    int size;
}VNode[MAX_VERTEX_NUM];
 
struct Graph{
    VNode nodes;
    int n, e;
};
int dist[MAX_VERTEX_NUM];
int cost[MAX_VERTEX_NUM];
bool visited[MAX_VERTEX_NUM];
//Edge edges[MAX_EDGE_NUM];
void allocateArcNode(ArcNode** arcNode)
{
    *arcNode = (ArcNode*)malloc(sizeof(ArcNode));
    (*arcNode)->nextarc = NULL;
}
 
void initeGraph(Graph &graph)
{
    for (int i = 1; i <= MAX_VERTEX_NUM; i++)
    {
        graph.nodes[i].firstArc = NULL;
        graph.nodes[i].size = 0;
    }
 
    graph.n = 0;
    graph.e = 0;
}
 
void createGraph(Graph &graph, int m)
{
    int v1, v2, len, cost;
    ArcNode* p1 = NULL;
    ArcNode* p2 = NULL;
    for (int i = 1; i <= m; i++)
    {
        allocateArcNode(&p1);
        allocateArcNode(&p2);
        cin >> v1 >> v2 >> len >> cost;
        p1->vertex = v2;
        p1->len = len;
        p1->cost = cost;
        p1->nextarc = graph.nodes[v1].firstArc;
        graph.nodes[v1].firstArc = p1;
        graph.nodes[v1].size++;
        p2->vertex = v1;
        p2->len = len;
        p2->cost = cost;
        p2->nextarc = graph.nodes[v2].firstArc;
        graph.nodes[v2].firstArc = p2;
        graph.nodes[v2].size++;
    }
}
 
//void printGraph(const Graph& graph, int n)
//{
//  for (int i = 1; i <= n; i++)
//  {
//      ArcNode* arcPtr = graph.nodes[i].firstArc;
//
//      cout << i << ":    ";
//      cout << "size:" << graph.nodes[i].size << endl;
//      while (arcPtr != NULL)
//      {
//          cout << arcPtr->len << ‘ ‘ << arcPtr->cost << ";";
//          arcPtr = arcPtr->nextarc;
//      }
//
//      cout << endl;
//  }
//}
 
void dijkStra(const Graph &graph, int v0, int n)
{
    int index = v0;
    dist[v0] = 0;
    cost[v0] = 0;
    visited[v0] = true;
    for (int i = 1; i <= n; i++)
    {
        ArcNode *arcPtr = graph.nodes[index].firstArc;
        while (arcPtr != NULL)
        {
            int tmp = arcPtr->vertex;
            int len = arcPtr->len;
            int co = arcPtr->cost;
            if ((visited[tmp] == false) && (dist[tmp] > dist[index] + len 
                || (dist[tmp] == dist[index] + len && cost[tmp] > cost[index] + co)))
            {
                dist[tmp] = dist[index] + len;
                cost[tmp] = cost[index] + co;
            }
            arcPtr = arcPtr->nextarc;
        }
        int minLen = MAXVALUE;
        int minCost = MAXVALUE;
        for (int j = 1; j <= n; j++)
        {
            if (visited[j] == true || dist[j] == MAXVALUE)
                continue;
            if (dist[j] < minLen || (dist[j] == minLen && cost[j] < minCost))
            {
                minLen = dist[j];
                minCost = cost[j];
                index = j;
            }
        }
        visited[index] = true;
    }
}
 
void freeSpaceOfGraph(Graph& graph)
{
    for (int i = 1; i <= graph.n; i++)
    {
        ArcNode *arcPtr = graph.nodes[i].firstArc;
        while (arcPtr != NULL)
        {
            ArcNode *tmp = arcPtr;
            arcPtr = arcPtr->nextarc;
            delete tmp;
        }
    }
}
 
int main()
{
    int n, m;
 
    while (cin >> n >> m)
    {
        if (n == 0 && m == 0)
            break;
        int start, end;
 
        for (int i = 1; i <= n; i++)
        {
            visited[i] = false;
            cost[i] = MAXVALUE;
            dist[i] = MAXVALUE;
        }
 
        Graph graph;
        initeGraph(graph);
        graph.n = n;
        graph.e = m;
        createGraph(graph, m);
        cin >> start >> end;
        dijkStra(graph, start, n);
        cout << dist[end] << ‘ ‘ << cost[end] << endl;
        freeSpaceOfGraph(graph);
    }
    return 0;
}
 
 
/**************************************************************
    Problem: 1008
    User: 凌月明心
    Language: C++
    Result: Accepted
    Time:10 ms
    Memory:1528 kb
****************************************************************/

View Code

终于AC了“最短路径”

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原文地址：http://www.cnblogs.com/tgycoder/p/5025914.html

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