多段图动态规划算法的实现(DP)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <conio.h>
#include <limits.h>

#define MAX_VERTEX_NUM 20
#define MAX_VALUE_TYPE INT_MAX

typedef int VertexType;


typedef struct node{
    VertexType adjvex;
    int weight; //权值
    struct node *next;
}EdgeNode;

typedef struct vnode{
    VertexType vertex;  //顶点域
    EdgeNode *firstedge;
}VertexNode;

typedef VertexNode AdjList[MAX_VERTEX_NUM];

typedef struct{
    AdjList adjlist;
    int n,e;    //顶点数和边数
}ALGraph;
/*
int Locate(ALGraph *G, int n){
    int i;
    for(i=0; i<G->n; i++){
        if(G->adjlist[i].vertex == n) return i;
    }
    return -1;
}*/

void CreateALGraph(ALGraph *G){//建立有向图的邻接表
    int i,j;
    int k;
    EdgeNode *s;
    scanf("%d%d", &G->n, &G->e);
    for(i=0; i<G->n; i++){
        scanf("%d", &G->adjlist[i].vertex);//G->adjlist[i].vertex = getch();
        G->adjlist[i].firstedge = NULL; //边表设置成空表
    }
    for(k=0; k<G->e; k++){
        scanf("%d%d", &i, &j);
    //    i = Locate(G, i); j = Locate(G, j); //查找结点序号
        s = (EdgeNode *)malloc(sizeof(EdgeNode));
        scanf("%d", &s->weight);
        s->adjvex = j;  //邻接点序号为j
        s->next = G->adjlist[i].firstedge;
        G->adjlist[i].firstedge = s;

        //无向图时加上
     //   s = (EdgeNode *)malloc(sizeof(EdgeNode));
     //   s->adjvex = i;
     //   s->next = G->adjlist[j].firstedge;
     //   G->adjlist[j].firstedge = s;
    }
}

VertexType fgraph(ALGraph *G, int route[], int n){
    int i;
    EdgeNode *pnode;

    int *path = (int *)malloc(n*sizeof(int));
    VertexType min_cost, *cost = (VertexType*)malloc(n*sizeof(VertexType));
    for(i=0; i<n; i++){
        cost[i] = MAX_VALUE_TYPE; path[i] = -1; route[i] = 0;
    }
    cost[n-1] = 0;
    for(i=n-1; i>=0; i--){
        pnode = G->adjlist[i].firstedge;
        while(pnode != NULL){
            if(pnode->weight + cost[pnode->adjvex] < cost[i]){
                cost[i] = pnode->weight + cost[pnode->adjvex];
                path[i] = pnode->adjvex;
            }
            pnode = pnode->next;
        }
    }
    i = 0;
    while((route[i] != n-1) && (path[i] != -1)){
        i++;
        route[i] = path[route[i-1]];
    }
    min_cost = cost[0];
    free(path); free(cost);
    return min_cost;
}


void print(ALGraph *G){
    EdgeNode *p;
    int i;
    for(i=0; i<G->n; i++){
        printf("index %d VERTEX %d", i, G->adjlist[i].vertex);
        for(p = G->adjlist[i].firstedge; p; p = p->next){
            printf("->\tVERTEX %d weight %d", p->adjvex, p->weight);
        }
        putchar('\n');
    }
}

int main(){
    freopen("d:\\my.txt", "r", stdin);
    int route[MAX_VERTEX_NUM];
    ALGraph G;
    CreateALGraph(&G);
    print(&G);
    printf("%d", fgraph(&G, route, G.n));
    int i;
    for(i=0; i<G.n; i++){
        printf("\t%d", route[i]);
    }
    return 0;
}
my.txt

10 19
0 1 2 3 4 5 6 7 8 9
0 1 4
0 2 1
0 3 3
2 3 1
1 4 9
1 5 8
2 4 6
2 5 7
2 6 8
3 5 4
3 6 7
4 7 5
4 8 6
5 7 8
5 8 6
6 7 6
6 8 5
7 9 7
8 9 3