oj.uz

Submission #207305

# Submission time Handle Problem Language Result Execution time Memory
207305 2020-03-07T05:41:59 Z dolphingarlic Palinilap (COI16_palinilap) C++14
100 / 100
 109 ms 25080 KB 
#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
using namespace std;

const ll M = 1e9 + 9, P = 9973;

ll pw[100001];

int n;
string s[2];
ll hsh[100001][2], 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) % M + s[j][i]) % M;
}

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

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]) % M;
	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 11 ms 1528 KB Output is correct
4 Correct 7 ms 1016 KB Output is correct
5 Correct 8 ms 1400 KB Output is correct
6 Correct 9 ms 1528 KB Output is correct
7 Correct 9 ms 1528 KB Output is correct

Subtask #3
46.0 / 46.0

# Verdict Execution time Memory Grader output
1 Correct 105 ms 24824 KB Output is correct
2 Correct 72 ms 24824 KB Output is correct
3 Correct 73 ms 24824 KB Output is correct
4 Correct 99 ms 24824 KB Output is correct
5 Correct 104 ms 24824 KB Output is correct
6 Correct 100 ms 24824 KB Output is correct
7 Correct 102 ms 24824 KB Output is correct
8 Correct 59 ms 4536 KB Output is correct
9 Correct 94 ms 24800 KB Output is correct
10 Correct 97 ms 24824 KB Output is correct
11 Correct 74 ms 24824 KB Output is correct
12 Correct 109 ms 25080 KB Output is correct
13 Correct 105 ms 24824 KB Output is correct
14 Correct 96 ms 24824 KB Output is correct
15 Correct 104 ms 24824 KB Output is correct
16 Correct 90 ms 24824 KB Output is correct
17 Correct 98 ms 24828 KB Output is correct
18 Correct 103 ms 24824 KB Output is correct
19 Correct 99 ms 24944 KB Output is correct