Something

#include <iostream.h>
#include <stdlib.h>
#include <string.h>
#include <vector>


#define INPROCESS 1
#define FINISHED 2
#define NOTFINISHED 0
#define ON 1
#define OFF 0

using namespace std;
typedef vector<int> ADJLIST;

struct vert{
	int vnum,val,time;
	char color;
};

struct vert* ans;
int n,t;
ADJLIST* vmat;


void print_exit()
{
	cout << "0";
	exit(1);
}


void DFS(int x)
{
	ADJLIST::iterator itr;
	if(ans[x].color == FINISHED)
		return;
	ans[x].color = INPROCESS;
	for(itr=vmat[x].begin();itr != vmat[x].end();itr++){
		if(ans[*itr].color == INPROCESS)//its a cycle-->no topological ordering exists
			print_exit();
		if(ans[*itr].color == NOTFINISHED)
			DFS(*itr);
	}
	ans[x].color = FINISHED;
	ans[x].vnum = x;
	ans[x].time = t++;
}

int compare(const void* a,const void* b)
{
	return(((struct vert*)a) ->time - ((struct vert*)b) ->time);
}


int compare2(const void* a,const void* b)
{
	return(((struct vert*)a) ->vnum - ((struct vert*)b) ->vnum);
}


void findans()
{
	int i = 0;
	for(i = 1;i <= n;i++)
		if(ans[i].color == NOTFINISHED)
			DFS(i);
	
	qsort(ans,n+1,sizeof(vert),compare);//sort based on finish time
	for(i = 1;i <= n;i++)
		ans[i].val = i;
	qsort(ans,n+1,sizeof(vert),compare2);//sort based on the vertex number
	cout << "1\n";
	int count = 1,x,xlim=1;
	for(;;){
		for(x = 0;x < xlim;x++,count++){
			cout << ans[count].val;
			if(x != xlim-1)
				cout << " ";
		}
		if(count > n)
			break;
		cout << "\n";
		xlim += 2;
	}
}



int main()
{
	int i = 0,lim = 0,j = 0,diff = 2,count = 1;
	cin >> n;
	char adjstr[200],verstr[200];
	lim = (2*n) - 2;
	int temp,len,flag = ON;

	n *= n;//nsquare triangles-->each triangle represents a vertex
	vmat = new ADJLIST[n+1];
	ans = new vert[n+1];
	ans[0].time=-2;
	ans[1].color = NOTFINISHED;
	//first row
	cin >> verstr;
	if(count+diff <= n)
		verstr[0] == '>' ? vmat[count].push_back(count+diff) : vmat[count+diff].push_back(count);
	
	//other rows
	for(i = 1,count = 2,diff+=2;i < lim-1;i+=2,diff+=2){
		cin >> adjstr >> verstr;
		temp = count;
		len = strlen(adjstr);
		for(j = 0;j < len;j++,count++)
			adjstr[j] == '>' ? vmat[count].push_back(count+1) : vmat[count+1].push_back(count);
		
		count = temp;
		len = strlen(verstr);
		flag = ON;
		for(j = 0;j < len;j++,count++){
			ans[count].color = NOTFINISHED;
			if(count+diff > n )
				continue;
			if(flag == OFF){
				flag = ON;
				j--;
				continue;
			}
			verstr[j] == '>' ? vmat[count].push_back(count+diff) : vmat[count+diff].push_back(count);
			flag = OFF;
		}
	}

	//last row
	cin >> adjstr;
	len = strlen(adjstr);
	for(i = 0;i < len;i++,count++){
		ans[count].color = NOTFINISHED;
		adjstr[i] == '>' ? vmat[count].push_back(count+1) : vmat[count+1].push_back(count);
	}
	t = 1;
	findans();
	
	return 0;

}