Submission #857971

#	Time	Username	Problem	Language	Result	Execution time	Memory
857971		TAhmed33	Linear Garden (IOI08_linear_garden)	C++98	100 / 100	106 ms	29252 KiB

linear_garden

#include <bits/stdc++.h>
using namespace std;
int m;
int add (int a, int b) {
	a += b; if (a >= m) a -= m;
	return a;
}
int sub (int a, int b) {
	a -= b; if (a < 0) a += m;
	return a;
}
int mul (int a, int b) {
	return (a * 1ll * b) % m;
}
int dp[2][5][5][5];
string s;
inline int get (int a, int b, int c, int d) {
	if (d < 0 || d > 4) return 0;
	if (b < 0 || b > 4) return 0;
	if (c < 0 || c > 4) return 0;
	return dp[a & 1][b][c][d];
}
int main () {
	int n;
	cin >> n >> m;
	cin >> s;
	vector <vector <int>> x;
	int a = 2, b = 2, c = 2;
	int sum = 1;	
	for (int i = 0; i < n; i++) {
		if (s[i] == 'P') {
			x.push_back({(int)s.length() - i - 1, min(c + 1, a), max(c + 1, b), c + 1});
			c--; a = min(a, c); b = max(b, c);
		} else {
			c++; a = min(c, a); b = max(b, c);
		}
	}
	for (int j = 0; j <= 2; j++) for (int k = 2; k <= min(4, j + 2); k++) for (int l = j; l <= k; l++) dp[0][j][k][l] = 1;
	for (int i = 0; i <= n; i++) {
		if (i) for (int j = 0; j <= 2; j++) { //low
			for (int k = 2; k <= min(4, j + 2); k++) { //high
				for (int l = j; l <= k; l++) {
					int &ret = dp[i & 1][j][k][l];
					ret = 0;
					ret = add(ret, get(i - 1, min(j, l - 1), max(k, l - 1), l - 1));
					ret = add(ret, get(i - 1, min(j, l + 1), max(k, l + 1), l + 1));
				}
			}
		}
		if (!x.empty() && x.back()[0] == i) {
			sum = add(sum, get(i, x.back()[1], x.back()[2], x.back()[3]));
			x.pop_back();
		}
	}
	cout << sum << '\n';
}

• Subtask 1: 2 / 2
• Subtask 2: 2 / 2
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
• Subtask 6: 4 / 4
• Subtask 7: 4 / 4
• Subtask 8: 4 / 4
• Subtask 9: 4 / 4
• Subtask 10: 4 / 4
• Subtask 11: 4 / 4
• Subtask 12: 5 / 5
• Subtask 13: 5 / 5
• Subtask 14: 5 / 5
• Subtask 15: 5 / 5
• Subtask 16: 5 / 5
• Subtask 17: 5 / 5
• Subtask 18: 5 / 5
• Subtask 19: 5 / 5
• Subtask 20: 5 / 5
• Subtask 21: 5 / 5
• Subtask 22: 5 / 5
• Subtask 23: 5 / 5