int main()
{
int n, p;
cin >> n >> p;
vector<int> viout(n), viin(n), vito(n), vifrom(n);
for(int i = 0; i < p; i++)
{
int a, b, d; cin >> a >> b >> d;
a--; b--;
viout[a] = d; vito[a] = b;
viin[b] = d; vifrom[b] = a;
}
vector<int> ans_a, ans_b, ans_c;
vector<int> done(n);
for(int i = 0; i < n; i++)
{
if(viin[i] == 0 && viout[i] != 0)
{
pair<int,int> p = solve(viout, viin, vito, vifrom, i, 100000000, done);
if(p.first != -1)
{
ans_a.push_back(i);
ans_b.push_back(p.first);
ans_c.push_back(p.second);
}
}
}
cout << ans_a.size() << endl;
for(int i = 0; i < ans_a.size(); i++)
cout << ans_a[i] + 1 << " " << ans_b[i] + 1 << " " << ans_c[i] << endl;
return 0;
}
/*
* Insert character c at current cursor position.
* Multi-character inserts occur only as a result
* of expansion of tabs (i.e. inssize == 1 except
* for tabs) and code assumes this in several place
* to make life simpler.
*/
int
vinschar(int c)
/* int c; /\* mjm: char --> int */
{
register int i;
register cell *tp;
char *OIM;
bool OXN;
int noim, filler = 0;
insmc1 = colsc(c) - 1;
if ((!IM || !EI) && ((hold & HOLDQIK) || !value(REDRAW) || value(SLOWOPEN))) {
/*
* Don't want to try to use terminal
* insert mode, or to try to fake it.
* Just put the character out; the screen
* will probably be wrong but we will fix it later.
*/
if (c == '\t') {
vgotab();
return c;
}
vputchar(c);
#ifdef MB
if (insmc1 == 0 && (vtube0[destcol]&(TRIM|MULTICOL))==MULTICOL)
vtube0[destcol] = INVBIT;
#endif /* MB */
if (DEPTH(vcline) * WCOLS + !value(REDRAW) >
(destline - LINE(vcline)) * WCOLS + destcol)
return c;
/*
* The next line is about to be clobbered
* make space for another segment of this line
* (on an intelligent terminal) or just remember
* that next line was clobbered (on a dumb one
* if we don't care to redraw the tail.
*/
if (AL) {
vnpins(0);
} else {
c = LINE(vcline) + DEPTH(vcline);
if (c < LINE(vcline + 1) || c > WBOT)
return c;
i = destcol;
vinslin(c, 1, vcline);
DEPTH(vcline)++;
vigoto(c, i);
vprepins();
}
return c;
}
/*
* Compute the number of positions in the line image of the
* current line. This is done from the physical image
* since that is faster. Note that we have no memory
* from insertion to insertion so that routines which use
* us don't have to worry about moving the cursor around.
*/
if (*vtube0 == 0)
linend = 0;
else {
/*
* Search backwards for a non-null character
* from the end of the displayed line.
*/
i = WCOLS * DEPTH(vcline);
if (i == 0)
i = WCOLS;
tp = vtube0 + i;
while (*--tp == 0)
if (--i == 0)
break;
linend = i + insmc1;
}
/*
* We insert at a position based on the physical location
* of the output cursor.
*/
inscol = destcol + (destline - LINE(vcline)) * WCOLS;
insmc0 = 0;
#ifdef MB
i = 0;
while (inscol+i < LBSIZE && vtube0[inscol+i]&MULTICOL &&
(vtube0[inscol+insmc0+i]&(MULTICOL|TRIM)) != MULTICOL)
i++;
while (inscol+insmc0+i < LBSIZE &&
(vtube0[inscol+insmc0+i]&(MULTICOL|TRIM)) == MULTICOL)
insmc0++;
#endif /* MB */
if (c == '\t') {
/*
* Characters inserted from a tab must be
* remembered as being part of a tab, but we can't
* use QUOTE here since we really need to print blanks.
* QUOTE|' ' is the representation of this.
*/
inssiz = tabcol(inscol+insmc0, value(TABSTOP)) - inscol - insmc0;
c = ' ' | QUOTE;
} else
inssiz = 1;
/*
* If the text to be inserted is less than the number
* of doomed positions, then we don't need insert mode,
* rather we can just typeover.
*/
if (inssiz + insmc1 <= doomed) {
endim();
if (inscol + insmc0 != linend)
doomed -= inssiz + insmc1;
#ifdef MB
if (insmc1 == 0 && c != '\t' &&
vtube0[inscol+insmc0] & MULTICOL)
vtube0[inscol+insmc0] = INVBIT;
#endif /* MB */
do
vputchar(c);
while (--inssiz);
return c;
}
/*
* Have to really do some insertion, thus
* stake out the bounds of the first following
* group of tabs, computing starting position,
* ending position, and the number of ``spaces'' therein
* so we can tell how much it will squish.
*/
tp = vtube0 + inscol + insmc0;
for (i = inscol + insmc0; i < linend; i++) {
if (*tp++ & QUOTE) {
--tp;
break;
}
}
tabstart = tabend = i;
tabslack = 0;
while (tabend < linend) {
i = *tp++;
if ((i & QUOTE) == 0)
break;
if ((i & (TRIM|MULTICOL)) == 0)
tabslack++;
tabsize++;
tabend++;
}
tabsize = tabend - tabstart;
/*
* For HP's and DM's, e.g. tabslack has no meaning.
*/
if (!IN)
tabslack = 0;
#ifdef IDEBUG
if (trace) {
fprintf(trace, "inscol %d, inssiz %d, tabstart %d, ",
inscol, inssiz, tabstart);
fprintf(trace, "tabend %d, tabslack %d, linend %d\n",
tabend, tabslack, linend);
}
#endif
OIM = IM;
OXN = XN;
noim = 0;
#ifdef MB
if (mb_cur_max > 1) {
if (destcol + 1 + insmc1 == WCOLS + 1) {
noim = 1;
if (insmc1 == 1 && insmc0 == 0)
filler = 1;
}
for (i = inscol; vtube0[i]; i++)
if (i + 1 >= WCOLS && vtube0[i] & MULTICOL) {
noim = 1;
break;
}
}
#endif /* MB */
if (noim) {
endim();
IM = 0;
XN = 0;
}
/*
* The real work begins.
*/
slakused = 0;
shft = 0;
if (tabsize) {
/*
* There are tabs on this line.
* If they need to expand, then the rest of the line
* will have to be shifted over. In this case,
* we will need to make sure there are no ``spaces''
* in the rest of the line (on e.g. CONCEPT-100)
* and then grab another segment on the screen if this
* line is now deeper. We then do the shift
* implied by the insertion.
*/
if (inssiz >= doomed + tabcol(tabstart, value(TABSTOP)) - tabstart) {
if (IN)
vrigid();
vneedpos(value(TABSTOP));
vishft();
}
} else if (inssiz + insmc1 > doomed)
/*
* No tabs, but line may still get deeper.
*/
vneedpos(inssiz + insmc1 - doomed);
/*
* Now put in the inserted characters.
*/
viin(c);
/*
* Now put the cursor in its final resting place.
*/
destline = LINE(vcline);
destcol = inscol + inssiz + insmc1 + filler;
vcsync();
if (IM != OIM) {
IM = OIM;
XN = OXN;
}
return c;
}