Submission #1003139

#	Time	Username	Problem	Language	Result	Execution time	Memory
1003139		fryingduc	Difference (POI11_roz)	C++17	100 / 100	766 ms	13360 KiB

roz

#include "bits/stdc++.h"
using namespace std;

#define SZ(a) (int)(a).size()
#define ALL(a) (a).begin(),(a).end()

signed main() {
	int n;
	cin >> n;
	vector<vector<int>> pos(26);
	for (int i = 1; i <= n; ++i) {
		char c; cin >> c;
		pos[int(c - 'a')].push_back(i);
	}
	int ans = 0;
	for (int x = 0; x < 26; ++x) {
		for (int y = 0; y < 26; ++y) {
			if (x == y) {
				continue;
			}
			if (!SZ(pos[x]) || !SZ(pos[y])) {
				continue;
			}
			vector<int> a = {0};
			{
				int j = 0;
				for (int i : pos[x]) {
					while (j < SZ(pos[y]) && pos[y][j] < i) {
						a.push_back(-1);
						j++;
					}
					a.push_back(1);
				}
				while (j < SZ(pos[y])) {
					a.push_back(-1);
					j++;
				}
			}
			int sz = SZ(a);
			int mn = n + 1, lst = 0;
			vector<int> pref(sz, 0);
			for (int i = 1; i < sz; ++i) {
				pref[i] = pref[i - 1] + a[i];
				if (i > 1 && a[i] != a[i - 1]) {
					for (int j = lst; j < i - 1; ++j) {
						mn = min(mn, pref[j]);
					}
					lst = i - 1;
				}
				ans = max(ans, pref[i] - mn);
			}
		}
	}
	cout << ans << '\n';
	return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10