int fun(){
int k;
bool flag;
for(k=1; k<=num; k++){
sum[k].undef = true;
}
sum[0].l = 0; sum[0].r = 0; sum[0].undef = false;
Ran one;
flag = true;
while( flag ){
flag = false;
for(int i=0; i<cnt; i++){
if(sum[tree[i].s].undef && sum[tree[i].n].undef){
continue;
}
if(sum[tree[i].s].undef){
flag = true;
one = sum[tree[i].n];
if(tree[i].cmp == 1){
one.less(-tree[i].v);
} else {
one.great(-tree[i].v);
}
sum[tree[i].s] = one;
} else if(sum[tree[i].n].undef){
flag = true;
one = sum[tree[i].s];
if(tree[i].cmp ==1){
one.great(tree[i].v);
} else {
one.less(tree[i].v);
}
sum[tree[i].n] = one;
} else { // detect conflicts.
one = sum[tree[i].s];
if(tree[i].cmp ==1){
one.great(tree[i].v);
} else {
one.less(tree[i].v);
}
one.inter(sum[tree[i].n]);
if(one.r < one.l) return 0;
if(sum[tree[i].n] != one){
sum[tree[i].n] = one;
flag = true;
}
one = sum[tree[i].n];
if(tree[i].cmp == 1){
one.less(-tree[i].v);
} else {
one.great(-tree[i].v);
}
one.inter(sum[tree[i].s]);
if(one != sum[tree[i].s]){
sum[tree[i].s] = one;
flag = true;
}
}
}
if(flag == false){
for(k=1;k<=num;k++){
if(sum[k].undef){
flag = true;
sum[k].undef = false;
sum[k].l = sum[k].r = 0;
break;
}
}
}
}
return 1;
}
