图算法之图的最长路径

来自UNSW的一个C语言大作业，滴滴滴滴滴滴

#include <stdlib.h>#include <stdio.h>#include <string.h>#include <assert.h>#include <stdbool.h>typedef struct GraphRep *Graph;// vertices are intstypedef int Vertex;// edges are pairs of vertices (end-points)typedef struct Edge {    Vertex v;    Vertex w;} Edge;typedef struct GraphRep {    int  **edges;   // adjacency matrix    int    nV;      // #vertices    int    nE;      // #edges} GraphRep;bool found;Graph newGraph(int V) {    assert(V >= 0);    int i;    Graph g = (Graph )malloc(sizeof(GraphRep));//  Graph g = NULL;    assert(g != NULL);    g->nV = V;    g->nE = 0;    // allocate memory for each row    g->edges =(int **) malloc(V * sizeof(int *));    assert(g->edges != NULL);    // allocate memory for each column and initialise with 0    for (i = 0; i < V; i++) {        g->edges[i] =(int *)calloc(V, sizeof(int));        assert(g->edges[i] != NULL);    }    return g;}// check if vertex is valid in a graphbool validV(Graph g, Vertex v) {    return (g != NULL && v >= 0 && v < g->nV);}void insertEdge(Graph g, Edge e) {    assert(g != NULL && validV(g, e.v) && validV(g, e.w));    if (!g->edges[e.v][e.w]) {  // edge e not in graph        g->edges[e.v][e.w] = 1;        //        g->edges[e.w][e.v] = 1;        g->nE++;    }}void removeEdge(Graph g, Edge e) {    assert(g != NULL && validV(g, e.v) && validV(g, e.w));    if (g->edges[e.v][e.w]) {   // edge e in graph        g->edges[e.v][e.w] = 0;        g->edges[e.w][e.v] = 0;        g->nE--;    }}bool adjacent(Graph g, Vertex v, Vertex w) {    assert(g != NULL && validV(g, v) && validV(g, w));    return (g->edges[v][w] != 0);}void showGraph(Graph g, char** corpus) {    assert(g != NULL);    int i = 0, j = 0;    for (i = 0; i < g->nV; i++){        printf("%s: ", corpus[i]);        for (j = 0; j < g->nV; j++){            if (adjacent(g, i, j))                printf("%s ", corpus[j]);        }        printf("\n");    }    printf("\n");}void freeGraph(Graph g) {    assert(g != NULL);    int i;    for (i = 0; i < g->nV; i++)        free(g->edges[i]);    free(g->edges);    free(g);}void print_chain(Vertex v, Vertex const visited[], int size, char** corpus){    //int print_arr[size];    int print_arr[1000];    int i = size - 1;    while (v != visited[v]) {        print_arr[i--] = v;        v = visited[v];    }    print_arr[i] = v;    printf("%s", corpus[print_arr[0]]);    for (i = 1; i < size; i++)        printf(" -> %s", corpus[print_arr[i]]);    printf("\n");}void _longest_path(Graph g, Vertex prev, Vertex v, Vertex visited[], int current, int target, char** corpus){    assert(visited[v] == -1);    visited[v] = prev;    if (current == target){        if (!found) {            found = true;            printf("Maximum chain length: %d\n", target);            printf("Maximal chains:\n");        }        print_chain(v, visited, current, corpus);        return;    }    int w;    for (w = 0; w < g->nV; w++)    if (adjacent(g, v, w) && visited[w] == -1)        _longest_path(g, v, w, visited, current + 1, target, corpus);    visited[v] = -1;}void LongestPath(Graph g, char** corpus){    found = false;    //Vertex visited[g->nV];    Vertex visited[1000];    int i, v, max_dist;    for (i = 0; i < g->nV; i++)        visited[i] = -1;    for (max_dist = g->nV; max_dist > 0; max_dist--) {        if (found)            return;        for (v = 0; v < g->nV; v++)        if (visited[v] == -1)            _longest_path(g, v, v, visited, 1, max_dist, corpus);    }}int CompareTwoWords(char word1[], char word2[]){    int len1 = strlen(word1);    int len2 = strlen(word2);    if (abs((int)(len1-len2)) > 1){ //if more than two,prove false        return 0;    }    //if equal    if (len1 == len2){        int pos = 0;        int i;        for (i = 0; i < len1; i++){            if (word1[i] != word2[i]){                pos = i;                int j;                for (j = pos + 1; j < len1; j++){                    if (word1[j] != word2[j]){                        return 0;                    }                }                break;            }        }    }    //if left for one char distance,for code length,deal with something    else{        char str_large[20], str_small[20];        if (len1 > len2){            strcpy(str_large, word1);            strcpy(str_small, word2);        }        else if (len1 < len2){            strcpy(str_large, word2);            strcpy(str_small, word1);        }        int i;        for (i = 0; i < strlen(str_small); i++){            if (str_small[i] != str_large[i]){                int pos = i;                int j;                for (j = pos; j < strlen(str_small); j++){                    if (str_small[j] != str_large[j + 1]){                        return 0;                    }                }                break;            }        }    }    return 1;}void init(){    int n;    char *s[1000];    printf("Enter a num:");    scanf("%d", &n);    Graph Graph = newGraph(n);    Edge e;    getchar();    int i;    for (i = 0; i < n; i++){        s[i] =(char *) malloc(sizeof(char)*20);        printf("Enter word:");        gets(s[i]);    }    int temp_count = 0;    for (i = 0; i < n; i++){        temp_count = i + 1;        printf("%s: ", s[i]);        while (temp_count != n){            if (temp_count == i){                temp_count++;                continue;            }            if (CompareTwoWords(s[i], s[temp_count])){                printf("%s ", s[temp_count]);                //填充边                e.v = i;                e.w = temp_count;                insertEdge(Graph, e);            }            temp_count++;        }        printf("\n");    }    LongestPath(Graph, s);}int main(){    init();    system("pause");    return 0;}