I want to ask how can come up with the solution in a short time. Sorry for my weak English.

GL && HF!

Today is my birthday!

Seems a lot easier than previous contests. G is only 575.

GL&&HF!

Problem C is too difficult!

C is way much harder than a 300-score problem, I think it worth at least 400.

F was beautiful!

For E, my only observation is:

For some number, says, 349685

Ans = 333333 + 2 * 44444 + 3 * 9999 + 4 * 666 + 5 * 88 + 6 * 5

But this will definitely get TLE, so how the hell did u guys manage to solve it?

I unaccepted C at about 20:30,and I dont accept so far,but I dont know why I unaccepted.

I assumed the input for boxes containing stones was sorted. Was wondering why getting WA the entire time ;)

Why bruteforce works for D? Solution

How to solve E? My approach is to consider the contribution of each digit, but used High Precision which caused TLE. :(

My bad for not checking conditions, but still not to sort input in C was totally unnecessary :(

Anybody can explain me the F problem ;-;

C was hard

Could not optimize to final state

felt F was a next greatest ele problem but got confused from the testcases?

Example:

2 1 4 3 5

query: 1 and 2

expected ans: 2 (buildings with heights 3 and 5)

how is 1 able to see 3 and 5 ? isn't it blocked by 4 (building 3)

E made me laugh because I thought it was a easy simulation problem haha. Surprisingly, I got a 2210 runtime running at $$$O(n^2)$$$. I read the editorial last night and it had such a beautiful solution. 10/10 contest.

Can someone help with finding what's wrong with my submission for problem C https://atcoder.jp/contests/abc379/submissions/59600147

when the Testcases will be updated in dropbox and then i can download the wrong test?

Could someone tell me where am wrong in C ? I've tried many times, but didn't accepted yet.... Below is my code. ~~~~~

define _CRT_SECURE_NO_WARNINGS

include <bits/stdc++.h>

using ll = long long int; using namespace std;

struct ch { ll x, y; } a[200005];

bool cmp(ch q, ch p) { return q.x < p.x; }

int main() { ll n, m; cin >> n >> m;

for (int i = 1; i <= m; i++)
    cin >> a[i].x;
for (int i = 1; i <= m; i++)
    cin >> a[i].y;

sort(a + 1, a + m + 1, cmp);
ll ans = 0;
for (int i = 1; i < m; i++)
{
    ll gap = a[i + 1].x - a[i].x - 1;
    ll d = gap * (gap + 1) / 2;
    if (gap == 0)
    {
        a[i + 1].y += a[i].y - 1;
        ans += a[i].y - 1;
    }
    if (gap <= a[i].y - 1&&gap!=0)
    {
        a[i + 1].y += a[i].y - 1 - gap; 
        ans += d;
    }
    if(gap>a[i].y-1)
    {
        cout << -1 << endl;
        return 0;
    }
}
ll last_gap = n - a[m].x;
ll last_cost = last_gap * (last_gap + 1) / 2;

if (last_gap < a[m].y - 1)
{
    cout << -1 << endl;
    return 0;
}
else
{
    ans += last_cost;
}

cout << ans << endl;
return 0;

} ~~~~~

Why no blog of ABC380 yet?