Hello, about 4 months ago i tried to solve [problem:678F] using LI Chao tree and trick to delete lines from it([trick](https://cp-algorithms.com/data_structures/deleting_in_log_n.html)), but got WA9. After that i stopped trying to solve it. But today i started from the very beginning and still it is WA9. Here is my last submission: [submission:100175660]. Can you help me?↵
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UPD:↵
I finally found where was an error. I used pointer incorrectly, here is solution that works: [submission:100181898]. If someone else is facing same problem try to write your update like this:↵
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~~~~~↵
node* upd(pll val, node *v = r, ll tl = -inf, ll tr = inf) {↵
if (v == nullptr)↵
v = new node();↵
ll tm = tl + tr >> 1;↵
if (v->val.F * tm + v->val.S <= val.F * tm + val.S) {↵
s.push({v, v->val});↵
swap(val, v->val);↵
}↵
if (tl + 1 == tr)↵
return v;↵
if (v->val.F * tl + v->val.S >= val.F * tl + val.S)↵
v->r = upd(val, v->r, tm, tr);↵
else↵
v->l = upd(val, v->l, tl, tm);↵
return v;↵
}↵
~~~~~↵
↵
In solution with an error i made upd as a void function, i think that i need to improve my understanding of pointers in C++.↵
↵
↵
↵
↵
UPD:↵
I finally found where was an error. I used pointer incorrectly, here is solution that works: [submission:100181898]. If someone else is facing same problem try to write your update like this:↵
↵
↵
~~~~~↵
node* upd(pll val, node *v = r, ll tl = -inf, ll tr = inf) {↵
if (v == nullptr)↵
v = new node();↵
ll tm = tl + tr >> 1;↵
if (v->val.F * tm + v->val.S <= val.F * tm + val.S) {↵
s.push({v, v->val});↵
swap(val, v->val);↵
}↵
if (tl + 1 == tr)↵
return v;↵
if (v->val.F * tl + v->val.S >= val.F * tl + val.S)↵
v->r = upd(val, v->r, tm, tr);↵
else↵
v->l = upd(val, v->l, tl, tm);↵
return v;↵
}↵
~~~~~↵
↵
In solution with an error i made upd as a void function, i think that i need to improve my understanding of pointers in C++.↵
↵
