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답안 #724727

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
724727 2023-04-15T19:28:57 Z ParsaAp Sparklers (JOI17_sparklers) C++14
100 / 100
 203 ms 13300 KB 
#include <bits/stdc++.h>
#define pb push_back
#define SZ(x) ((int) x.size())
#define all(x) x.begin(), x.end()
#define ld long double
#define ll long long
using namespace std;

const int N = 1e5 + 111;
const ld INF = 1e17;
int n, k;
ld T, X[N];
vector <ld> a[2], ps[2]; int mxn[2], p[2], nxt[2]; ld mn[2];

ld g(int x) {
	return ps[x][p[x]];
}

void go_next(int x) {
	nxt[x] = p[x] + 1;
	mn[x] = INF;
	while (nxt[x] <= mxn[x] && ps[x][nxt[x]] < ps[x][p[x]]) {
		mn[x] = min(mn[x], ps[x][nxt[x]]);
		nxt[x]++;
	}
}

void set_next(int x) {
	p[x] = nxt[x];
	go_next(x);
}

bool check2() {
	for (int i = 0; i < 2; i++) {
		p[i] = nxt[i] = mn[i] = 0;
	}
	if (g(0) + g(1) < 0) return 0;
	go_next(0);
	go_next(1);
	while (nxt[0] <= mxn[0] || nxt[1] <= mxn[1]) {
		if (nxt[0] <= mxn[0] && mn[0] + g(1) >= 0ll) {
			set_next(0);
		}
		else if (nxt[1] <= mxn[1] && mn[1] + g(0) >= 0) {
			set_next(1);
		}
		else return 0;
	}
	return 1;
}

bool check(int s) {

	a[0].clear(), a[1].clear();

	a[0].pb(T);
	for (int i = k + 1; i < n; i++) {
		a[0].pb(-(X[i] - X[i - 1]) * 1. / (2 * s));
		a[0].pb(T);
	}
	for (int i = k - 1; ~i; i--) {
		a[1].pb(-(X[i + 1] - X[i]) * 1. / (2 * s));
		a[1].pb(T);
	}

	ps[0].clear();
	ps[1].clear();
	for (int i = 0; i < 2; i++) {
		ps[i].pb(0);
		for (auto j: a[i]) {
			ps[i].pb(ps[i].back() + j);
		}
		mxn[i] = max_element(all(ps[i])) - ps[i].begin();
	}
	bool ans = check2();
	for (int i = 0; i < 2; i++) {
		reverse(all(ps[i]));
		mxn[i] = SZ(ps[i]) - 1 - mxn[i];
	}
	ans = ans & check2();
	return ans;
}

void solve() {
	if (X[n - 1] == 0) {
		cout << 0;
		return;
	}
	int L = 0, R = 1e9 + 1;
	while (L + 1 < R) {
		int m = (L + R) / 2;
		if (check(m)) {
			R = m;
		}
		else {
			L = m;
		}
	}
	cout << R;
}

void read() {
	cin >> n >> k >> T;
	k--;
	for (int i = 0; i < n; i++) {
		cin >> X[i];
	}
}

int main() {
	ios::sync_with_stdio(0), cin.tie(0);

	read();
	solve();
}

Subtask #1
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 0 ms 340 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 0 ms 328 KB Output is correct
12 Correct 1 ms 340 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 324 KB Output is correct
17 Correct 0 ms 340 KB Output is correct
18 Correct 1 ms 332 KB Output is correct
19 Correct 0 ms 328 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct

Subtask #2
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 0 ms 340 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 0 ms 328 KB Output is correct
12 Correct 1 ms 340 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 324 KB Output is correct
17 Correct 0 ms 340 KB Output is correct
18 Correct 1 ms 332 KB Output is correct
19 Correct 0 ms 328 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 2 ms 340 KB Output is correct
23 Correct 2 ms 340 KB Output is correct
24 Correct 2 ms 340 KB Output is correct
25 Correct 2 ms 468 KB Output is correct
26 Correct 2 ms 476 KB Output is correct
27 Correct 3 ms 468 KB Output is correct
28 Correct 3 ms 468 KB Output is correct
29 Correct 2 ms 464 KB Output is correct
30 Correct 3 ms 468 KB Output is correct
31 Correct 2 ms 468 KB Output is correct
32 Correct 2 ms 340 KB Output is correct
33 Correct 3 ms 340 KB Output is correct
34 Correct 3 ms 468 KB Output is correct
35 Correct 3 ms 468 KB Output is correct
36 Correct 3 ms 468 KB Output is correct
37 Correct 3 ms 464 KB Output is correct
38 Correct 3 ms 468 KB Output is correct
39 Correct 3 ms 468 KB Output is correct
40 Correct 1 ms 340 KB Output is correct

Subtask #3
50.0 / 50.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 0 ms 340 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 0 ms 328 KB Output is correct
12 Correct 1 ms 340 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 324 KB Output is correct
17 Correct 0 ms 340 KB Output is correct
18 Correct 1 ms 332 KB Output is correct
19 Correct 0 ms 328 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 2 ms 340 KB Output is correct
23 Correct 2 ms 340 KB Output is correct
24 Correct 2 ms 340 KB Output is correct
25 Correct 2 ms 468 KB Output is correct
26 Correct 2 ms 476 KB Output is correct
27 Correct 3 ms 468 KB Output is correct
28 Correct 3 ms 468 KB Output is correct
29 Correct 2 ms 464 KB Output is correct
30 Correct 3 ms 468 KB Output is correct
31 Correct 2 ms 468 KB Output is correct
32 Correct 2 ms 340 KB Output is correct
33 Correct 3 ms 340 KB Output is correct
34 Correct 3 ms 468 KB Output is correct
35 Correct 3 ms 468 KB Output is correct
36 Correct 3 ms 468 KB Output is correct
37 Correct 3 ms 464 KB Output is correct
38 Correct 3 ms 468 KB Output is correct
39 Correct 3 ms 468 KB Output is correct
40 Correct 1 ms 340 KB Output is correct
41 Correct 139 ms 8116 KB Output is correct
42 Correct 5 ms 724 KB Output is correct
43 Correct 39 ms 2384 KB Output is correct
44 Correct 194 ms 12896 KB Output is correct
45 Correct 198 ms 10316 KB Output is correct
46 Correct 193 ms 12344 KB Output is correct
47 Correct 203 ms 12312 KB Output is correct
48 Correct 196 ms 10824 KB Output is correct
49 Correct 193 ms 12112 KB Output is correct
50 Correct 194 ms 10448 KB Output is correct
51 Correct 198 ms 12480 KB Output is correct
52 Correct 198 ms 13300 KB Output is correct
53 Correct 203 ms 13112 KB Output is correct
54 Correct 201 ms 13236 KB Output is correct
55 Correct 193 ms 10316 KB Output is correct
56 Correct 192 ms 12756 KB Output is correct
57 Correct 200 ms 13232 KB Output is correct
58 Correct 195 ms 10840 KB Output is correct
59 Correct 12 ms 2004 KB Output is correct
60 Correct 192 ms 13252 KB Output is correct
61 Correct 197 ms 13124 KB Output is correct
62 Correct 199 ms 12656 KB Output is correct
63 Correct 188 ms 13244 KB Output is correct
64 Correct 191 ms 10092 KB Output is correct
65 Correct 189 ms 10912 KB Output is correct
66 Correct 193 ms 10440 KB Output is correct
67 Correct 194 ms 11032 KB Output is correct
68 Correct 198 ms 13156 KB Output is correct
69 Correct 197 ms 13228 KB Output is correct