Submission #537047

#	Time	Username	Problem	Language	Result	Execution time	Memory
537047		pavement	Dango Maker (JOI18_dango_maker)	C++17	100 / 100	230 ms	18100 KiB

dango_maker

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
#define int long long
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ppb pop_back
#define eb emplace_back
#define g0(a) get<0>(a)
#define g1(a) get<1>(a)
#define g2(a) get<2>(a)
#define g3(a) get<3>(a)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
using db = double;
using ll = long long;
using ld = long double;
using ii = pair<int, int>;
using iii = tuple<int, int, int>;
using iiii = tuple<int, int, int, int>;
template<class key, class value = null_type, class cmp = less<key> >
using ordered_set = tree<key, value, cmp, rb_tree_tag, tree_order_statistics_node_update>;

int N, M, ans, dp[6005][3];
char C[3005][3005];

main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> N >> M;
	for (int i = 1; i <= N; i++)
		for (int j = 1; j <= M; j++) cin >> C[i][j];
	for (int j = 1; j <= M; j++) {
		// diagonal ends at (1, j)
		int idx = 1;
		for (int r = 1, c = j; r <= N && 1 <= c; r++, c--, idx++) {
			if (C[r][c] == 'R') {
				for (int k = 0; k <= 2; k++) {
					dp[idx][k] = dp[idx - 1][max(0ll, k - 1)];
					if (k == 0 && r + 2 <= N && C[r + 1][c] == 'G' && C[r + 2][c] == 'W') dp[idx][k] = max(dp[idx][k], dp[idx - 1][0] + 1);
					if (c + 2 <= M && C[r][c + 1] == 'G' && C[r][c + 2] == 'W') dp[idx][k] = max(dp[idx][k], dp[idx - 1][2] + 1);
				}
			} else {
				for (int k = 0; k <= 2; k++)
					dp[idx][k] = dp[idx - 1][max(0ll, k - 1)];
			}
		}
		ans += dp[idx - 1][0];
	}
	for (int i = 2; i <= N; i++) {
		// diagonal ends at (i, M)
		int idx = 1;
		for (int r = i, c = M; r <= N && 1 <= c; r++, c--, idx++) {
			if (C[r][c] == 'R') {
				for (int k = 0; k <= 2; k++) {
					dp[idx][k] = dp[idx - 1][max(0ll, k - 1)];
					if (k == 0 && r + 2 <= N && C[r + 1][c] == 'G' && C[r + 2][c] == 'W') dp[idx][k] = max(dp[idx][k], dp[idx - 1][0] + 1);
					if (c + 2 <= M && C[r][c + 1] == 'G' && C[r][c + 2] == 'W') dp[idx][k] = max(dp[idx][k], dp[idx - 1][2] + 1);
				}
			} else {
				for (int k = 0; k <= 2; k++)
					dp[idx][k] = dp[idx - 1][max(0ll, k - 1)];
			}
		}
		ans += dp[idx - 1][0];
	}
	cout << ans << '\n';
}

Compilation message (stderr)

dango_maker.cpp:32:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   32 | main() {
      | ^~~~

• Subtask 1: 13 / 13
• Subtask 2: 20 / 20
• Subtask 3: 67 / 67