Congrats heqr for getting a bronze medal.

Hard luck Essa2006, it was just 9 points from the bronze medal.

Best wishes for the Saudi team in next IOIs.

A: Security check in websites that want to prevent robots, just print "security"

B: The first 25 contests in codeforces, contests 15, 20, and 21 was unrated, so print NO if the contest was unrated, otherwise print YES

C: Every testcase will give you n numbers, where $$$n = PI_i$$$, so $$$n1 = 3$$$, $$$n2 = 1$$$, $$$n3 = 4$$$, and so on.., Print the product of numbers

D: Print any number that is guranteed that it won't come in the sequence, for example 0 or -1

E: Print any positive number (I don't know)

F: Print largest prime factor, don't calculate it, just put if

G: The image shows that he is a color blind, n is the length, s1 is what person sees, s2 is what is the real colors. Print YES if the person only sees the red color correctly.

H: Complex probabilities problem, because all the numbers are random (idk the solution)

I: Check if the bracket sequence is balanced, Consider letters "bdfhklt" as open bracket, and letters "gjpqy" as closed bracket, ignore other letters

J: Write "please" in any lettercase, and judge will give you AC

Recently, I solved 342E - Ксюша и дерево using Sqrt decomposition.

The problem have two types of queries:

• Color node $$$x$$$ red
• Find minimum distance to any red color

I thought, what will be the solution if there is query: Color node $$$x$$$ blue?

I'm not sure if this is solvable using centroid decomposition, but is there another way?

I thought long time ago, why std doesn't have a segment_tree class? so I decided to create a similar one.

My template is a class in an STD-similar way, supporting lazy propagation.

A quick example on how does it look like:

#include <bits/stdc++.h>
using namespace std;
// Put the template here :)
using namespace alg;

segment_tree<int, merge_min> st;

int main() {
    int n, q;
    cin >> n;
    st.set_out(INT_MAX);
    st.resize(n);
    for (int i = 0; i < n; i++)
        cin >> st.values[i];
    st.build();
    cin >> q;
    while (q--) {
        int l, r;
        cin >> l >> r;
        l--, r--;
        cout << st.get(l, r) << '\n';
    }
}

Just like that!!

It's available on a GitHub gist

So, what is your opinion about it? and how can I improve it?