07-图4 哈利·波特的考试

小白专场里说的很清楚，前面代码的拼凑。

#include <cstdio>
#include <stdlib.h>

#define MaxVertexNum 100    /* 最大顶点数设为100 */
#define INFINITY 65535        /* ∞设为双字节无符号整数的最大值65535*/
typedef int Vertex;         /* 用顶点下标表示顶点,为整型 */
typedef int WeightType;        /* 边的权值设为整型 */


/* 边的定义 */
typedef struct ENode *PtrToENode;
struct ENode{
    Vertex V1, V2;      /* 有向边<V1, V2> */
    WeightType Weight;  /* 权重 */
};
typedef PtrToENode Edge;

/* 图结点的定义 */
typedef struct GNode *PtrToGNode;
struct GNode{
    int Nv;  /* 顶点数 */
    int Ne;  /* 边数   */
    WeightType G[MaxVertexNum][MaxVertexNum]; /* 邻接矩阵 */
    
};
typedef PtrToGNode MGraph; /* 以邻接矩阵存储的图类型 */



MGraph CreateGraph( int VertexNum )
{ /* 初始化一个有VertexNum个顶点但没有边的图 */
    Vertex V, W;
    MGraph Graph;
    
    Graph = (MGraph)malloc(sizeof(struct GNode)); /* 建立图 */
    Graph->Nv = VertexNum;
    Graph->Ne = 0;
    /* 初始化邻接矩阵 */
    /* 注意：这里默认顶点编号从0开始，到(Graph->Nv - 1) */
    for (V=0; V<Graph->Nv; V++)
        for (W=0; W<Graph->Nv; W++)
            Graph->G[V][W] = INFINITY;
    
    return Graph;
}

void InsertEdge( MGraph Graph, Edge E )
{
    /* 插入边 <V1, V2> */
    Graph->G[E->V1][E->V2] = E->Weight;
    /* 若是无向图，还要插入边<V2, V1> */
    Graph->G[E->V2][E->V1] = E->Weight;
}

MGraph BuildGraph()
{
    MGraph Graph;
    Edge E;
    int Nv, i;
    
    scanf("%d", &Nv);   /* 读入顶点个数 */
    Graph = CreateGraph(Nv); /* 初始化有Nv个顶点但没有边的图 */
    
    scanf("%d", &(Graph->Ne));   /* 读入边数 */
    if ( Graph->Ne != 0 ) { /* 如果有边 */
        E = (Edge)malloc(sizeof(struct ENode)); /* 建立边结点 */
        /* 读入边，格式为"起点 终点 权重"，插入邻接矩阵 */
        for (i=0; i<Graph->Ne; i++) {
            scanf("%d %d %d", &E->V1, &E->V2, &E->Weight);
            E->V1--; E->V2--;
            InsertEdge( Graph, E );
        }
    }
    
    return Graph;
}

void Floyd( MGraph Graph, WeightType D[][MaxVertexNum] )
{
    Vertex i, j, k;
    
    /* 初始化 */
    for ( i=0; i<Graph->Nv; i++ )
        for( j=0; j<Graph->Nv; j++ ) {
            D[i][j] = Graph->G[i][j];
           
        }
    
    for( k=0; k<Graph->Nv; k++ )
        for( i=0; i<Graph->Nv; i++ )
            for( j=0; j<Graph->Nv; j++ )
                if( D[i][k] + D[k][j] < D[i][j] ) {
                    D[i][j] = D[i][k] + D[k][j];
                   
                }
    for (int i=0; i<Graph->Nv; i++) {
        for(int j=0; j<Graph->Nv; j++){
            if(i == j) D[i][j] = INFINITY;
        }
    }
 
}

WeightType FindMaxDist(WeightType D[][MaxVertexNum], Vertex i, int Nv) {

    WeightType MaxDist = 0;
    for (Vertex j=0; j<Nv; j++) {
        if(i != j and D[i][j] > MaxDist) {
            MaxDist = D[i][j];
        }
    }
    return MaxDist;
    
}
void FindAnimal(MGraph Graph) {
    WeightType D[MaxVertexNum][MaxVertexNum], MinDist, MaxDist;
    Vertex Animal, i;
    Floyd(Graph, D);
    
    MinDist = INFINITY;
    for ( i=0; i<Graph->Nv; i++ ) {
        MaxDist = FindMaxDist(D, i, Graph->Nv);
        if (MaxDist == INFINITY) {
            printf("0\n");
            return;
        }
        if (MaxDist < MinDist) {
            MinDist = MaxDist;
            Animal = i+1;
        }
    }
    printf("%d %d\n", Animal, MinDist);
    
}



int main()
{
    MGraph G = BuildGraph();
    FindAnimal( G );
    return 0;
}