Submission #908807

#	Time	Username	Problem	Language	Result	Execution time	Memory
908807		MinaRagy06	Misspelling (JOI22_misspelling)	C++17	89 / 100	4021 ms	249372 KiB

misspelling

#include <bits/stdc++.h>
using namespace std;
#define ll long long

const int mod = 1e9 + 7;
struct mint {
	int v;
	mint(long long x) {
		if (x >= mod) x %= mod;
		v = x;
	}
	mint() {v = 0;}
	mint& operator+=(mint b) {
		if ((v += b.v) >= mod) {
			v -= mod;
		}
		return *this;
	}
	mint& operator-=(mint b) {
		if ((v -= b.v) < 0) {
			v += mod;
		}
		return *this;
	}
	mint& operator*=(mint b) {
		v = 1ll * v * b.v % mod;
		return *this;
	}
	mint power(mint a, int b) {
		mint ans = 1;
		while (b) {
			if (b & 1) {
				ans *= a;
			}
			a *= a, b >>= 1;
		}
		return ans;
	}
	mint& operator/=(mint b) {
		v = 1ll * v * power(b, mod - 2).v % mod;
		return *this;
	}
	friend mint operator+(mint a, mint b) {
		return a += b;
	}
	friend mint operator-(mint a, mint b) {
		return a -= b;
	}
	friend mint operator*(mint a, mint b) {
		return a *= b;
	}
	friend mint operator/(mint a, mint b) {
		return a /= b;
	}
	friend istream& operator>>(istream &is, mint a) {
		return is >> a.v;
	}
	friend ostream& operator<<(ostream &os, mint a) {
		return os << a.v;
	}
};

int main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	int n, m;
	cin >> n >> m;
	vector<int> st[n][2];
	for (int i = 0; i < m; i++) {
		int a, b;
		cin >> a >> b;
		a--, b--;
		if (a < b) {
			//s[i - 1] > s[i]
			st[a + 1][0].push_back(b + 1);
		} else {
			//s[i - 1] < s[i]
			st[b + 1][1].push_back(a + 1);
		}
	}
	mint dp[n + 1][26], prfx[n + 1][26], sufx[n + 1][26];
	for (int j = 0; j < 26; j++) prfx[n][j] = sufx[n][j] = dp[n][j] = 1;
	for (int j = 1; j < 26; j++) prfx[n][j] += prfx[n][j - 1];
	for (int j = 24; j >= 0; j--) sufx[n][j] += sufx[n][j + 1];
	set<int> active[26][2];
	mint sum[26][2];
	for (int i = n - 1; i >= 0; i--) {
		for (int j = 0; j < 26; j++) {
			active[j][0].insert(i);
			if (j - 1 >= 0) sum[j][0] += prfx[i + 1][j - 1];
			active[j][1].insert(i);
			if (j + 1 < 26) sum[j][1] += sufx[i + 1][j + 1];
			for (auto en : st[i][0]) {
				auto it = active[j][1].lower_bound(i);
				while (it != active[j][1].end() && *it < en) {
					if (j + 1 < 26) sum[j][1] -= sufx[*it + 1][j + 1];
					active[j][1].erase(it);
					it = active[j][1].lower_bound(i);
				}
			}
			for (auto en : st[i][1]) {
				auto it = active[j][0].lower_bound(i);
				while (it != active[j][0].end() && *it < en) {
					if (j - 1 >= 0) sum[j][0] -= prfx[*it + 1][j - 1];
					active[j][0].erase(it);
					it = active[j][0].lower_bound(i);
				}
			}
			prfx[i][j] = sufx[i][j] = dp[i][j] = sum[j][0] + sum[j][1] + 1;
		}
		for (int j = 1; j < 26; j++) {
			prfx[i][j] += prfx[i][j - 1];
		}
		for (int j = 24; j >= 0; j--) {
			sufx[i][j] += sufx[i][j + 1];
		}
	}
	mint ans = 0;
	for (int j = 0; j < 26; j++) {
		ans += dp[1][j];
	}
	cout << ans << '\n';
	return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 20 / 20
• Subtask 3: 29 / 29
• Subtask 4: 32 / 32
• Subtask 5: 0 / 11