hdu 1385 最短路+输出字典序好题

http://acm.hdu.edu.cn/showproblem.php?pid=1385

题意：求起点到终点的最短路，注意点是有权值的。然后要按找字典序输出路径。

分析：说实话这题卡了我好久，从数据没过到坑坑爹爹的把数据过了，再到改啊改一直ｗａ,我已经很满足了因为我耐住了性子，其实我一点也不希望他ac，要不然太没劲了。好吧这题wa了我18次。关键的地方就是按照字典序输出，由于我以前是按照另外一种方法存储路径导致一直wa。现在换一种方法。

// I'm lanjiangzhou
//C
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <time.h>
//C++
#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <cctype>
#include <stack>
#include <string>
#include <list>
#include <queue>
#include <map>
#include <vector>
#include <deque>
#include <set>
using namespace std;

//*************************OUTPUT*************************
#ifdef WIN32
#define INT64 "%I64d"
#define UINT64 "%I64u"
#else
#define INT64 "%lld"
#define UINT64 "%llu"
#endif

//**************************CONSTANT***********************
#define INF 0x3f3f3f3f

// aply for the memory of the stack
//#pragma comment (linker, "/STACK:1024000000,1024000000")
//end

const int infmax = 100000000;
const int maxn = 510;
int n,m;
int edge[maxn][maxn];
int dis[maxn][maxn];
int path[maxn][maxn];
int nodeedge[maxn];

void floyd(){
    int len;
    for(int k=1;k<=n;k++){
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                len=dis[i][k]+dis[k][j]+nodeedge[k];
                if(dis[i][j]>len){
                    dis[i][j]=len;
                    path[i][j]=path[i][k];
                }
                else if(len==dis[i][j]){
                    if(path[i][j]>path[i][k]){
                        path[i][j]=path[i][k];
                }
            }
        }
    }
}
}

int main(){
    while(scanf("%d",&n)!=EOF){
        if(n==0) break;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                dis[i][j]=infmax;
            }
            dis[i][i]=0;
        }
        int w;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                scanf("%d",&w);
                if(w!=-1){
                    dis[i][j]=w;
                }
            }
        }
        for(int i=1;i<=n;i++){
            scanf("%d",&nodeedge[i]);
        }
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                path[i][j]=j;
            }
        }
        floyd();
        int start,end;
        while(scanf("%d%d",&start,&end)!=EOF){
            if(start==-1&&end==-1) break;
            if(dis[start][end]==infmax){
                printf("-1\n");
                continue;
            }
            if(start==end){
                printf("From %d to %d :\n",start,end);
                printf("Path: %d\n",start);
                printf("Total cost : 0\n\n");
                continue;
            }
            printf("From %d to %d :\n",start,end);
            printf("Path: %d",start);
            int k=start;
            while(k!=end){
                printf("-->%d",path[k][end]);
                k=path[k][end];
            }
            printf("\n");
            printf("Total cost : %d\n\n",dis[start][end]);
        }
    }
    return 0;
}

以前的存储路径是保存在shortest[]中的，可以借鉴一下，我觉得还是很好的，以后还是用上面代码中的path[][]...我wa怕了。。呵呵

// I'm lanjiangzhou
//C
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <time.h>
//C++
#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <cctype>
#include <stack>
#include <string>
#include <list>
#include <queue>
#include <map>
#include <vector>
#include <deque>
#include <set>
using namespace std;

//*************************OUTPUT*************************
#ifdef WIN32
#define INT64 "%I64d"
#define UINT64 "%I64u"
#else
#define INT64 "%lld"
#define UINT64 "%llu"
#endif

//**************************CONSTANT***********************
#define INF 0x3f3f3f3f

// aply for the memory of the stack
//#pragma comment (linker, "/STACK:1024000000,1024000000")
//end

const int infmax = 100000000;
const int maxn = 510;
int n,m;
int edge[maxn][maxn];
int dis[maxn][maxn];
int path[maxn][maxn];
int nodeedge[maxn];

void floyd(){
    int len;
    for(int k=1;k<=n;k++){
        for(int i=1;i<=n;i++){
            if(i==k||dis[i][k]==INF) continue;
            for(int j=1;j<=n;j++){
                if(i==k||k==j||dis[k][j]==INF) continue;
                len=dis[i][k]+dis[k][j]+nodeedge[k];
                if(dis[i][j]>len||dis[i][j]==INF){
                    dis[i][j]=dis[i][k]+dis[k][j]+nodeedge[k];
                    path[i][j]=path[k][j];
                }
                else if(len==dis[i][j]&&path[k][j]<path[i][j]){
                   // if(path[i][j]>path[k][j]){
                        path[i][j]=path[k][j];
                    //}
                }
               // printf("dis[i][j]=%d\n",dis[i][j]);
            }
        }
    }
}

int main(){
    while(scanf("%d",&n)!=EOF){
        //³õʼ»¯
        if(n==0) break;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                dis[i][j]=infmax;
                //if(i!=j&&dis[i][j]<INF) path[i][j]=i;
                //else path[i][j]=-1;
            }
            dis[i][i]=0;
        }
        int w;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                scanf("%d",&w);
                if(w==-1){
                    dis[i][j]=infmax;
                }
                else dis[i][j]=w;
            }
        }
//        for(int i=1;i<=n;i++){
//            for(int j=1;j<=n;j++){
//                printf("%d ",dis[i][j]);
//            }
//            printf("\n");
//        }
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                if(i!=j&&dis[i][j]!=infmax) path[i][j]=i;
                else path[i][j]=-1;
            }
        }
        for(int i=1;i<=n;i++){
            scanf("%d",&nodeedge[i]);
        }
        floyd();
        int start,end;
        int shortest[maxn];
        while(scanf("%d%d",&start,&end)!=EOF){
            if(start==-1&&end==-1) break;
            if(dis[start][end]==infmax){
                printf("-1\n");
                continue;
            }
            if(start==end){
                printf("From %d to %d :\n",start,end);
                printf("Path: %d\n",start);
                printf("Total cost : 0\n\n");
                continue;
            }
            printf("From %d to %d :\n",start,end);
            memset(shortest,0,sizeof(shortest));
            int k=0;
            shortest[k]=end;
            while(path[start][shortest[k]]!=start){
                k++;  shortest[k]=path[start][shortest[k-1]];
            }
            k++;  shortest[k]=start;
            printf("Path: ");
            for(int j=k;j>0;j--){
                printf("%d-->",shortest[j]);
            }
            printf("%d\n",shortest[0]);
            printf("Total cost : %d\n\n",dis[start][end]);
        }
    }
    return 0;
}