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답안 #653770

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
653770 2022-10-28T03:48:22 Z GusterGoose27 Žarulje (COI15_zarulje) C++11
100 / 100
 360 ms 21556 KB 
#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;

const int MOD = 1e9+7;
const int MAXN = 2e5+4;
int powers[MAXN];
int dp[MAXN];
int skip_dp[MAXN];
int ans[MAXN];
int fac[MAXN];
int facinv[MAXN];
pii cur_space[MAXN];
int n, q;

int bash(pii range) {
	if (range == pii(1, n-2)) return 1;
	if (powers[range.first-1] == powers[range.second+1])
		return (bash(pii(range.first-1, range.second))+bash(pii(range.first, range.second+1)) % MOD);
	if (powers[range.first-1] > powers[range.second+1]) return bash(pii(range.first-1, range.second));
	return bash(pii(range.first, range.second+1));
}

int expo(ll a, int b) {
	ll res = 1;
	while (b > 0) {
		if (b & 1) {
			res *= a;
			res %= MOD;
		}
		b >>= 1;
		a *= a;
		a %= MOD;
	}
	return res;
}

int c(int n, int k) {
	ll cur = fac[n];
	cur *= facinv[k];
	cur %= MOD;
	cur *= facinv[n-k];
	return (cur%MOD);
}

void solve() {
	ios_base::sync_with_stdio(false); cin.tie(NULL);
	cin >> n >> q;
	n += 2;
	fac[0] = 1;
	ll cur = 1;
	facinv[0] = 1;
	for (int i = 1; i <= n; i++) {
		cur *= i;
		cur %= MOD;
		fac[i] = cur;
		facinv[i] = expo(fac[i], MOD-2);
	}
	powers[0] = 0;
	powers[n-1] = 0;
	vector<pii> proc_order;
	for (int i = 1; i < n-1; i++) {
		cin >> powers[i];
		assert(powers[i] > 0);
		proc_order.push_back(pii(powers[i], i));
	}
	sort(proc_order.begin(), proc_order.end());
	set<int> completed_vals;
	dp[0] = dp[n-1] = 1;
	completed_vals.insert(0);
	completed_vals.insert(n-1);
	for (int r = 0; r < n-2;) {
		vector<int> to_add;
		vector<int> extra_consid;
		vector<int> skip_calc;
		int l = r;
		while (r < n-2 && proc_order[l].first == proc_order[r].first) r++;
		for (int curr = l; curr < r;) {
			int curl = curr;
			auto it = completed_vals.upper_bound(proc_order[curl].second);
			int rp = *it;
			it--;
			int lp = *it;
			vector<int> cur_posses;
			while (curr < r && *completed_vals.upper_bound(proc_order[curr].second) == rp) {
				cur_posses.push_back(proc_order[curr].second);
				to_add.push_back(proc_order[curr].second);
				curr++;
			}
			if (rp < n-1) skip_calc.push_back(cur_posses.back());
			cur_space[rp].first = cur_space[lp].second = cur_posses.size();
			extra_consid.push_back(lp);
			extra_consid.push_back(rp);
			for (int p = 0; p < cur_posses.size(); p++) {
				int i = cur_posses[p];
				ll curdp = dp[lp];
				curdp *= c(cur_posses.size(), p+1);
				curdp %= MOD;
				dp[i] = curdp;
				curdp = dp[lp];
				curdp *= c(cur_posses.size()-1, p);
				curdp %= MOD;
				ans[i] = curdp;
				if (p < cur_posses.size()-1) {
					curdp = dp[lp];
					curdp *= c(cur_posses.size()-1, p+1);
					curdp %= MOD;
					skip_dp[i] = curdp;
				}
			}
		}
		for (int m: skip_calc) {
			auto it = completed_vals.lower_bound(m);
			int rp = *it;
			int lp = *(--it);
			ll curdp;
			if (powers[lp] >= powers[rp]) curdp = skip_dp[lp];
			else curdp = dp[lp];
			curdp *= c(cur_space[rp].first+cur_space[rp].second, cur_space[rp].first);
			skip_dp[m] = (curdp % MOD);
		}
		for (int v: extra_consid) cur_space[v] = pii(0, 0);
		for (int v: to_add) completed_vals.insert(v);
	}
	for (int i = 1; i < n-1; i++) {
		if (powers[i-1] < powers[i]) ans[i] = dp[i-1];
		else ans[i] = skip_dp[i-1];
	}
	bool fail = 0;
	for (int i = 0; i < q; i++) {
		int x; cin >> x;
		// int b = bash(pii(x, x));
		cout << ans[x] << /*" " << b << */"\n";
		// if (b != ans[x]) fail = 1;
	}
	if (fail) cout << "FAIL\n";
}

void gen_case() {
	for (int i = 1; i <= n; i++) powers[i] = 1+(rand()%3);
}

int main() {
	solve();
	return 0;
	srand(time(0));
	while (1) {
		n = 10;
		gen_case();
		solve();
		for (int i = 1; i < n-1; i++) {
			int b = bash(pii(i, i));
			if (b != ans[i]) {
				for (int i = 0; i < n; i++) {
					cout << powers[i+1] << " ";
				}
				cout << endl;
				exit(0);
			}
		}
	}
}

Compilation message

zarulje.cpp: In function 'void solve()':
zarulje.cpp:97:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   97 |    for (int p = 0; p < cur_posses.size(); p++) {
      |                    ~~^~~~~~~~~~~~~~~~~~~
zarulje.cpp:107:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  107 |     if (p < cur_posses.size()-1) {
      |         ~~^~~~~~~~~~~~~~~~~~~~~

Subtask #1
22.0 / 22.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 2 ms 340 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 3 ms 472 KB Output is correct
5 Correct 2 ms 468 KB Output is correct
6 Correct 3 ms 476 KB Output is correct

Subtask #2
38.0 / 38.0

# 결과 실행 시간 메모리 Grader output
1 Correct 126 ms 8892 KB Output is correct
2 Correct 156 ms 17780 KB Output is correct
3 Correct 224 ms 17504 KB Output is correct
4 Correct 278 ms 18364 KB Output is correct
5 Correct 296 ms 18460 KB Output is correct
6 Correct 325 ms 18604 KB Output is correct
7 Correct 313 ms 18684 KB Output is correct

Subtask #3
40.0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 2 ms 340 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 3 ms 472 KB Output is correct
5 Correct 2 ms 468 KB Output is correct
6 Correct 3 ms 476 KB Output is correct
7 Correct 126 ms 8892 KB Output is correct
8 Correct 156 ms 17780 KB Output is correct
9 Correct 224 ms 17504 KB Output is correct
10 Correct 278 ms 18364 KB Output is correct
11 Correct 296 ms 18460 KB Output is correct
12 Correct 325 ms 18604 KB Output is correct
13 Correct 313 ms 18684 KB Output is correct
14 Correct 11 ms 1364 KB Output is correct
15 Correct 140 ms 10836 KB Output is correct
16 Correct 195 ms 21472 KB Output is correct
17 Correct 243 ms 19664 KB Output is correct
18 Correct 287 ms 21556 KB Output is correct
19 Correct 312 ms 19596 KB Output is correct
20 Correct 360 ms 20352 KB Output is correct
21 Correct 318 ms 20456 KB Output is correct