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Submission #207302

# Submission time Handle Problem Language Result Execution time Memory
207302 2020-03-07T05:37:14 Z dolphingarlic Palinilap (COI16_palinilap) C++14
54 / 100
 73 ms 24952 KB 
#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
typedef unsigned long long ull;
using namespace std;

const ll P = 31;

ull pw[100001];

int n;
string s[2];
ull hsh[100001][2];
ll created[100001][26], destroyed[100001][2];

void calc_hashes() {
	hsh[0][0] = hsh[0][1] = 1;
	FOR(i, 0, n) FOR(j, 0, 2)
		hsh[i + 1][j] = hsh[i][j] * P + (s[j][i] - 'a' + 1);
}

ull get_hash(int a, int b, bool reverse) {
	return hsh[b + 1][reverse] - hsh[a][reverse] * pw[b - a + 1];
}

bool is_palindrome(int a, int b, int c, int d) {
	return get_hash(a, b, false) == get_hash(n - d - 1, n - c - 1, true);
}

int main() {
	cin >> s[0];
	n = s[0].size();
	s[1] = s[0];
	reverse(s[1].begin(), s[1].end());
	
	pw[0] = 1;
	FOR(i, 0, n) pw[i + 1] = P * pw[i];
	calc_hashes();
	
	ll base = 0;
	FOR(i, 0, n) FOR(j, i, i + 2) {
		int l = 0, r = min(i + 1, n - j);
		while (l != r) {
			int mid = (l + r + 1) / 2;
			if (is_palindrome(i - mid + 1, i, j, j + mid - 1)) l = mid;
			else r = mid - 1;
		}
		int rad = r;
		base += rad;
		
		if (i == j) {
			destroyed[j + 1][0]--, destroyed[j + rad][0]++;
			destroyed[j + 1][1] += j + rad, destroyed[j + rad][1] -= j + rad;

			destroyed[i - rad + 1][0]++, destroyed[i][0]--;
			destroyed[i - rad + 1][1] -= i - rad, destroyed[i][1] += i - rad;
		} else {
			destroyed[j][0]--, destroyed[j + rad][0]++;
			destroyed[j][1] += j + rad, destroyed[j + rad][1] -= j + rad;

			destroyed[i - rad + 1][0]++, destroyed[i + 1][0]--;
			destroyed[i - rad + 1][1] -= i - rad, destroyed[i + 1][1] += i - rad;
		}
		
		int x = i - rad, y = j + rad;
		if (x < 0 || y >= n) continue;
		
		rad++;
		l = 0, r = min(i + 1, n - j) - rad;
		while (l != r) {
			int mid = (l + r + 1) / 2;
			if (is_palindrome(x - mid, x - 1, y + 1, y + mid)) l = mid;
			else r = mid - 1;
		}

		created[x][s[0][y] - 'a'] += r + 1;
		created[y][s[0][x] - 'a'] += r + 1;
	}
	
	ll best = 0, x = 0, y = 0;
	FOR(i, 0, n) {
		x += destroyed[i][0], y += destroyed[i][1];
		FOR(j, 0, 26) if (i != s[0][j] - 'a') {
			best = max(best, created[i][j] - i * x - y);
		}
	}
	
	cout << base + best;
	return 0;
}

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 376 KB Output is correct
2 Correct 5 ms 376 KB Output is correct
3 Correct 5 ms 376 KB Output is correct
4 Correct 5 ms 376 KB Output is correct
5 Correct 5 ms 376 KB Output is correct

Subtask #2
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 1528 KB Output is correct
2 Correct 7 ms 1528 KB Output is correct
3 Correct 7 ms 1528 KB Output is correct
4 Correct 6 ms 1148 KB Output is correct
5 Correct 7 ms 1404 KB Output is correct
6 Correct 7 ms 1528 KB Output is correct
7 Correct 7 ms 1528 KB Output is correct

Subtask #3
0 / 46.0

# Verdict Execution time Memory Grader output
1 Correct 70 ms 24952 KB Output is correct
2 Correct 49 ms 24952 KB Output is correct
3 Correct 49 ms 24824 KB Output is correct
4 Correct 61 ms 24824 KB Output is correct
5 Correct 61 ms 24824 KB Output is correct
6 Correct 67 ms 24952 KB Output is correct
7 Correct 61 ms 24824 KB Output is correct
8 Correct 37 ms 4600 KB Output is correct
9 Correct 62 ms 24824 KB Output is correct
10 Correct 60 ms 24952 KB Output is correct
11 Correct 46 ms 24952 KB Output is correct
12 Correct 67 ms 24952 KB Output is correct
13 Correct 73 ms 24952 KB Output is correct
14 Correct 62 ms 24824 KB Output is correct
15 Correct 63 ms 24824 KB Output is correct
16 Correct 63 ms 24952 KB Output is correct
17 Correct 63 ms 24824 KB Output is correct
18 Incorrect 63 ms 24824 KB Output isn't correct
19 Halted 0 ms 0 KB -