7.27.txt

数据结构实验 如下： Status Fibonacci(int k, int m, int &f) /* 求k阶斐波那契序列的第m项的值f */

Status SinglePath(ALGraph g, VertexType sv, VertexType tv, int k, char *sp)
/* Judge whether it exists a path from sv to tv with length k */
/* in graph g, return path using string sp if  exists.        */
{   //超级贱的题！存路径的数组要自己初始化。
    ArcNode * p;   
    int i, j, l, t;
    int len;
    i = LocateVex(g, sv);
    j = LocateVex(g, tv);
    if(i == j && k == 0) {
        len = strlen(sp);
        for(t = len; t >= 1; t--){
            sp[t] = sp[t-1];
        }
        sp[0] = g.vertices[i].data;
        sp[len+1] = '\0';
        return 1;
    }
    else if(k > 0){
        visited[i] = 1;
        for(p = g.vertices[i].firstarc; p; p = p->nextarc){
            l = p->adjvex;
            if(!visited[l] && SinglePath(g, g.vertices[l].data, tv, k-1, sp)){
                len = strlen(sp);
                for(t = len; t >= 1; t--){
                    sp[t] = sp[t-1];
                }
                sp[0] =  g.vertices[i].data;
                sp[len+1] = '\0';
                return 1;
            }
        }
        visited[i] = 0;
    }
    return 0;
}