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Toyota Programming Contest 2024#11（AtCoder Beginner Contest 379） Announcement
By atcoder_official, history, 6 weeks ago, In English

We will hold Toyota Programming Contest 2024#11（AtCoder Beginner Contest 379）.

We are looking forward to your participation!

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6 weeks ago, # |
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I want to ask how can come up with the solution in a short time. Sorry for my weak English.

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6 weeks ago, # |
  Vote: I like it +8 Vote: I do not like it

GL && HF!

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6 weeks ago, # |
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Today is my birthday!

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6 weeks ago, # |
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Seems a lot easier than previous contests. G is only 575.

$$$\Huge{\text{Good Luck & Have Fun!}}$$$
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6 weeks ago, # |
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GL&&HF!

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6 weeks ago, # |
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Problem C is too difficult!

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

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    6 weeks ago, # ^ |
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    EDIT: only ~3.1k solves o_O

    interesting; why do you think that? it seems like it only required sorting and speeding up the simulation with triangular numbers... (and it doesn't seem like basically bruteforcing the thing is hard to come up with but i'm probably biased here)

    though i did get stuck on C for some reason

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6 weeks ago, # |
  Vote: I like it +9 Vote: I do not like it

F was beautiful!

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6 weeks ago, # |
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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?

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6 weeks ago, # |
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I unaccepted C at about 20:30,and I dont accept so far,but I dont know why I unaccepted.

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6 weeks ago, # |
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I assumed the input for boxes containing stones was sorted. Was wondering why getting WA the entire time ;)

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6 weeks ago, # |
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Why bruteforce works for D? Solution

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    6 weeks ago, # ^ |
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    I didnt try hoping it wud get TLE

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    6 weeks ago, # ^ |
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    During he contest, I thought that was the intended solution. It works because a plant only be harvest(count/delete) for once.

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      6 weeks ago, # ^ |
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      I think it should TLE. Eg a case where the first 1e5 queries are type 1, and the next 1e5 queries are type 2. Even if you compress Type 2 queries, should still TLE if you alternate between type 1 and type 2 queries...

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        6 weeks ago, # ^ |
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        sorry, I missunderstood the OP's solution.

        But if the second operation was changed to something similar to lazy tag(then you insert -tag, and delete >= H-tag), then it works.

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

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    6 weeks ago, # ^ |
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    • I used the idea to "simulate how we simply add two or more numbers."
    • We will find the answer from last position to first position. First, store the contributions of all the digits.
    • For example:- In string 379 , 3 will come to the last position 1 time (Only 3), 7 will come to the last position 2 times(37 and 7), and 9 will come to the last position in some substring 3 times(379,79 and 9). Or we can say s[i] contribution to last position will be i+1 (0-based indexing).
    • Now, We will build the answer from last position from last position to first position. For this, we need to store "carry" term. After we process position i, we will delete the contribution of s[i] digit. At last, we will add if any carry left.
    • Submission Link — https://atcoder.jp/contests/abc379/submissions/59605521
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6 weeks ago, # |
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My bad for not checking conditions, but still not to sort input in C was totally unnecessary :(

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6 weeks ago, # |
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Anybody can explain me the F problem ;-;

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6 weeks ago, # |
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C was hard

Could not optimize to final state

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6 weeks ago, # |
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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)

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    6 weeks ago, # ^ |
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    You misread the example. It is building index 3 and 5 (not height) that can be seen. Building index 3's height is 4 and building index 5's height is 5.

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      6 weeks ago, # ^ |
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      ohh it was a previous greater + next greater combo

      damn could've solved it

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6 weeks ago, # |
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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.

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

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    6 weeks ago, # ^ |
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    Try this test case;

    Spoiler
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      6 weeks ago, # ^ |
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      Thanks, need to practice reading statements more carefully :)

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6 weeks ago, # |
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when the Testcases will be updated in dropbox and then i can download the wrong test?

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5 weeks ago, # |
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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;

} ~~~~~

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5 weeks ago, # |
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Why no blog of ABC380 yet?

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