Submission #1255919

#	Time	Username	Problem	Language	Result	Execution time	Memory
1255919		thdh__	Crossing (JOI21_crossing)	C++20	100 / 100	376 ms	30272 KiB

Main

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define eb emplace_back
#define pu push
#define ins insert
#define fi first
#define se second
#define all(a) a.begin(),a.end()
#define bruh ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fu(x,a,b) for (auto x=a;x<=b;x++)
#define fd(x,a,b) for (auto x=a;x>=b;x--)
#define int ll

using namespace std;
//mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());

/*
Competitive Programming notes that I need to study & fix my dumbass self:

1. Coding:
- Always be sure to check the memory of arrays (maybe use vectors), for loops
- Always try to maximize the memory if possible, even if you are going for subtasks
- Do not exploit #define int long long, it will kill you

2. Stress: 
- Always try generating big testcases and try if they run

3. Time management:
- Don't overcommit or undercommit, always spend a certain amount of time to think a problem, don't just look at it and say I'm fucked
- Do not spend too much time coding brute-force solutions, they should be easily-codable solutions that don't take up too much time

Time management schedule:
Offline / LAH days (4 problems - 3h):
15' thinking of solution / idea
1. no idea: skip
2. yes idea: continue thinking for <= 15'

+ implementing: <= 20'
+ brute-force: <= 5'
+ test generator: <= 5'

I hate offline because I am dumb
*/

typedef pair<int, int> ii;
const int N = 2e5+5;
const int B = 750;
const int base = 31;
const int mod = 1e9+7;
const int inf = 1e18;
using cd = complex<double>;
const long double PI = acos(-1);
int power(int a,int b) {ll x = 1;if (a >= mod) a%=mod; while (b) {if (b & 1) x = x*a % mod;a = a*a % mod;b>>=1;}return x;} 

string merge(string a, string b) 
{
	string c;
	for (int i = 0; i < a.size(); i++) 
	{
		if (a[i] == b[i]) c += a[i];
		else 
		{
			if (a[i] != 'J' && b[i] != 'J') c += 'J';
			else if (a[i] != 'I' && b[i] != 'I') c += 'I';
			else c += 'O';
		}
	}
	return c;
}

int h[N], p[N];
int pref[4][N];

int getid(char c) 
{
	if (c == 'J') return 1;
	else if (c == 'O') return 2;
	else return 3;
}

void precalc() 
{
	p[0] = 1;
	for (int i = 1; i < N; i++) p[i] = p[i-1] * base % mod;
	for (int i = 1; i <= 3; i++) 
	{
		for (int j = 1; j < N; j++) pref[i][j] = (pref[i][j-1] * base % mod + i) % mod;
	}
}

int gethash(string s) 
{
	int n = s.size();
	s = " " + s;
	for (int i = 1; i <= n; i++) h[i] = (h[i-1] * base % mod + getid(s[i])) % mod;
	return h[n];
}

int n,q;
string a,b,c,t;
map<int, int> check;

int st[4*N], lazy[4*N];

void build(int id, int l, int r) 
{
	if (l == r) 
	{
		st[id] = getid(t[l]);
		return;
	}
	int mid = l+r>>1;
	build(id*2, l, mid); build(id*2+1, mid+1, r);
	st[id] = (st[id*2] * p[r-mid] % mod + st[id*2+1]) % mod;
}

void push(int id, int l, int r) 
{
	int mid = l+r>>1;
	if (!lazy[id]) return;
	st[id*2] = pref[lazy[id]][mid-l+1], st[id*2+1] = pref[lazy[id]][r-mid];
	lazy[id*2] = lazy[id*2+1] = lazy[id];
	lazy[id] = 0;
}

void update(int id, int l, int r, int u, int v, int val) 
{
	if (l > v || r < u) return;
	if (u <= l && r <= v) 
	{
		st[id] = pref[val][r-l+1];
		lazy[id] = val;
		return;
	}
	int mid = l+r>>1;
	push(id, l, r);
	update(id*2, l, mid, u, v, val); update(id*2+1, mid+1, r, u, v, val);
	st[id] = (st[id*2] * p[r-mid] % mod + st[id*2+1]) % mod;
}

void solve()
{
	precalc();
	cin>>n>>a>>b>>c;
	check[gethash(a)] = check[gethash(b)] = check[gethash(c)] = check[gethash(merge(a,b))] = check[gethash(merge(b,c))] = check[gethash(merge(c,a))] = check[gethash(merge(a, merge(b,c)))] = check[gethash(merge(b, merge(a,c)))] = check[gethash(merge(c, merge(a,b)))] = 1;
	cin>>q>>t;
	t = ' ' + t;
	build(1,1,n);
	if (check[st[1]]) cout<<"Yes"<<endl;
	else cout<<"No"<<endl;
	while (q--) 
	{
		int l,r;
		char c;
		cin>>l>>r>>c;
		update(1,1,n,l,r,getid(c));
		if (check[st[1]]) cout<<"Yes"<<endl;
		else cout<<"No"<<endl;
	}
}

/*
Go through the mistakes you usually make and revise your code, for god's sake...
*/

signed main()
{
	bruh
	//freopen("input.inp","r",stdin);
	//freopen("output.inp","w",stdout);
	solve();
}

• Subtask 1: 3 / 3
• Subtask 2: 23 / 23
• Subtask 3: 23 / 23
• Subtask 4: 51 / 51