POJ1094 Sorting It All Out

POJ1094 Sorting It All Out

Time Limit: 1000MS Memory Limit: 10000K

Total Submissions: 18073 Accepted: 6145

Description

An ascending sorted sequence of distinct values is one in which some form of a less-than operator is used to order the elements from smallest to largest. For example, the sorted sequence A, B, C, D implies that A < B, B < C and C < D. in this problem, we will give you a set of relations of the form A < B and ask you to determine whether a sorted order has been specified or not.

Input

Input consists of multiple problem instances. Each instance starts with a line containing two positive integers n and m. the first value indicated the number of objects to sort, where 2 <= n <= 26. The objects to be sorted will be the first n characters of the uppercase alphabet. The second value m indicates the number of relations of the form A < B which will be given in this problem instance. Next will be m lines, each containing one such relation consisting of three characters: an uppercase letter, the character "<" and a second uppercase letter. No letter will be outside the range of the first n letters of the alphabet. Values of n = m = 0 indicate end of input.

Output

For each problem instance, output consists of one line. This line should be one of the following three: 

Sorted sequence determined after xxx relations: yyy...y. 

Sorted sequence cannot be determined. 

Inconsistency found after xxx relations. 

where xxx is the number of relations processed at the time either a sorted sequence is determined or an inconsistency is found, whichever comes first, and yyy...y is the sorted, ascending sequence. 

Sample Input

4 6

A

A

B

C

B

A

3 2

A

B

26 1

A

0 0

Sample Output

Sorted sequence determined after 4 relations: ABCD.

Inconsistency found after 2 relations.

Sorted sequence cannot be determined.

*******************************************************************

拓扑排序，第一次写，可惜不是一A是二A，5555.

#include
#include
#include
using namespace std;

int gra[30][30],n;
vectorls;
int vis[30],mark[30];

void dfs(int s)
{
    vis[s]++;
    if(vis[s]>=2)return ;
    for(int i=0;i>n>>m,n+m)
    {
        num=n;
        memset(gra,0,sizeof(gra));
        memset(mark,0,sizeof(mark));
        char str[10];
        int flag=0;
        for(int i=1;i<=m;i++)
        {
            cin>>str;
            if(flag)continue;
            int one=str[0]-'A',two=str[2]-'A';
            if(mark[two]==0)num--;
            mark[two]++;
            gra[one][two]=1;
            memset(vis,0,sizeof(vis));
            dfs(one);
            if(vis[one]>1)
            {
                flag=1;
                cout<<"Inconsistency found after "<

　　

转载于:https://www.cnblogs.com/Fatedayt/archive/2011/09/15/2178066.html