POJ 1094 sorting It all out topology sort

sorting It all OutTime limit:1000MS Memory Limit:10000KB 64bit IO Format:%lld &%llu< /c8>

Description

An ascending sorted sequence of distinct values are one in which some form of a less-than operator are used to order the Ele ments from smallest to largest. For example, the sorted sequence A, B, C, D implies, a < B, b < C and C < D. In this problem, we'll give yo U a set of relations of the form a < B and ask you to determine whether a sorted order have been specified or not.

Input

Input consists of multiple problem instances. Each instance starts with a line containing-positive integers n and m. The first value indicated the number of objects To sort, where 2 <= n <= 26. The objects to be sorted'll be the first n characters of the uppercase alphabet. The second value m indicates the number of relations of the form A < B which'll be given in this problem instance. Next'll be M lines, each containing one such relation consisting of three Characters:an uppercase letter, the character "<" and a second uppercase letter. No letter would 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, the output consists of one line. This line should is 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 are determined or an inconsistency is F Ound, whichever comes first, and yyy...y is the sorted, ascending sequence.

Sample Input

4 6a<ba<cb<cc<db<da<b3 2a<bb<a26 1a<z0 0

Sample Output

Sorted sequence determined after 4 RELATIONS:ABCD. Inconsistency found after 2 relations. Sorted sequence cannot be determined.



Set of templates

#include <iostream> #include <cstring> #include <cstdio> #include <algorithm> #include < queue> #include <vector> #include <iomanip> #include <math.h> #include <map>using namespace STD; #define FIN freopen ("Input.txt", "R", stdin), #define FOUT freopen ("Output.txt", "w", stdout); #define INF 0x3f3f 3f3f#define Lson l,m,rt<<1#define Rson m+1,r,rt<<1|1typedef long long ll;const int MAXN=1e5+5;struct EDG e{int v,nxt;} E[maxn*2];int head[maxn],erear;int in[maxn],p[maxn],sz;int temp[maxn];int n,m,sum;int flag,ed;bool con;void edge_init   () {erear=0;   memset (head,-1,sizeof (Head));   memset (In,0,sizeof (in));   sum=0; con=0;}   void Edge_add (int u,int v) {e[erear].v=v;   E[erear].nxt=head[u]; head[u]=erear++;}        int Topsort () {sz=0;        queue<int>q; for (int i=0;i<n;i++) {if (!        In[i]) Q.push (i);        } bool sign=0; while (!     Q.empty ()) {if (Q.size () >=2) sign=1;       int U=q.front ();            Q.pop ();            P[sz++]=u;                for (int i=head[u];~i;i=e[i].nxt) {int v=e[i].v;                in[v]--; if (!            IN[V]) Q.push (v);            }} if (Sz<n) {//printf ("invalid\n");        return 1;            }else if (sign) {//printf ("multi ans\n");        return 2;        }else{return 3;            }/*for (int i=0;i<sz;i++) {if (i==0) printf ("%d", p[i]);        else printf ("%d", p[i]); } printf ("\ n"); */}int main () {//fin while (~scanf ("%d%d", &n,&m)) {if (n==0&&m==0) b        Reak;        Edge_init ();        flag=2;        Char op[10];            for (int i=1;i<=m;i++) {scanf ("%s", op);            if (con) continue;            int u= (int) op[0]-' A ';            int v= (int) op[2]-' A ';                if (op[1]== ' > ') {edge_add (u,v);            in[v]++;      } else{          Edge_add (V,u);            in[u]++;            } memcpy (Temp,in,sizeof (in));            Flag=topsort ();            memcpy (in,temp,sizeof (temp));            Sum=i;                if (flag!=2) {ed=i;            Con=true;                }} if (flag==3) {printf ("Sorted sequence determined after%d relations:", ed);                   for (int i=sz-1; i>=0;-I.) printf ("%c", p[i]+ ' A ');            printf (". \ n");            } else if (flag==1) {printf ("inconsistency found after%d relations.\n", ed);            } else{printf ("Sorted sequence cannot be determined.\n"); }} return 0;}

　　

POJ 1094 sorting It all out topology sort