Submission #1253965

#	Time	Username	Problem	Language	Result	Execution time	Memory
1253965		thdh__	Copy and Paste 3 (JOI22_copypaste3)	C++20	100 / 100	276 ms	49704 KiB

copypaste3

#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 = 2500+5;
const int B = 750;
const int mod = 1e9+7;
const int base = 103;
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;} 

mt19937 rng(123);

int n,a,b,c;
string s;
int dp[N][N];
int h[N], p[N];
int nxt[N], val[N];
int hv[N];

int get(int l, int r) 
{
	return (h[r] - h[l-1] + mod) % mod * p[n-l] % mod;
}

void solve()
{
	cin>>n>>s>>a>>b>>c;
	s = ' ' + s;
	for (int i = 1; i <= n; i++) for (int j = 1; j <= n; j++) dp[i][j] = inf;
	for (int i = 1; i <= n; i++) dp[i][i] = a;
	p[0] = 1;
	for (int i = 1; i <= n; i++) p[i] = (p[i-1] * base) % mod;
	for (int i = 0; i <= 30; i++) hv[i] = rng() % mod;
	for (int i = 1; i <= n; i++) h[i] = (h[i-1] + hv[s[i]-'a'] * p[i] % mod) % mod;
	for (int len = 1; len <= n; len++) 
	{
		unordered_map<int, int> pos;
		for (int i = n; i >= len; i--) 
		{
			val[i] = get(i-len+1, i);
			nxt[i] = pos[val[i]];
			if (i+len-1 <= n) pos[val[i+len-1]] = i+len-1;
		}
		// cout<<len<<endl;
		// for (int i = len; i <= n; i++) 
		// {
		// 	cout<<val[i]<<" "<<nxt[i]<<endl;
		// }
		// cout<<endl;
		if (len > 1) 
		{
			for (int i = 1; i <= n-len+1; i++) dp[i][i+len-1] = min({dp[i][i+len-1], dp[i][i+len-2] + a, dp[i+1][i+len-1] + a}); 
		}
		for (int l = 1; l <= n-len+1; l++) 
		{
			int r = l+len-1, cnt = 1;
			while (r) 
			{
				dp[l][r] = min(dp[l][r], dp[l][l+len-1] + b + cnt * c + ((r-l+1) - cnt * len) * a);
				r = nxt[r];
				cnt++;
			}
		}
	}
	// for (int i = 1; i <= n; i++) 
	// {
	// 	for (int j = i; j <= n; j++) cout<<dp[i][j]<<" ";
	// 	cout<<endl;
	// }
	cout<<dp[1][n];
}

/*
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);
	int t = 1;
	// cin>>t;
	while (t--)
	{
		solve();
		cout<<"\n";
	}
}

• Subtask 1: 1 / 1
• Subtask 2: 5 / 5
• Subtask 3: 14 / 14
• Subtask 4: 10 / 10
• Subtask 5: 32 / 32
• Subtask 6: 38 / 38