1 files changed, 73 insertions, 0 deletions
diff --git a/21/open/balanced_slow.cpp b/21/open/balanced_slow.cpp
new file mode 100644
index 0000000..3f7c3e9
--- /dev/null
+++ b/21/open/balanced_slow.cpp
@@ -0,0 +1,73 @@
+#include <bits/stdc++.h>
+#define f first
+#define s second
+using namespace std;
+using ll = long long;
+using ii = pair<int, int>;
+constexpr int MX = 155, MOD = 1e9+7;
+
+inline void add(int & x, int y) { x += y; if (x > MOD) x -= MOD; }
+
+string S[MX];
+
+struct fenwick_tree_2d {
+	int FT[MX][MX];
+	fenwick_tree_2d() { memset(FT, 0, sizeof FT); }
+	inline void update(int x, int y, int v) {
+		for (int i = x+1; i < MX; i += i&-i)
+            for (int j = y+1; j < MX; j += j&-j) add(FT[i][j], v);
+    }
+    inline int query(int x, int y) {
+        int ret = 0;
+        for (int i = x+1; i > 0; i -= i&-i)
+            for (int j = y+1; j > 0; j -= j&-j) add(ret, FT[i][j]);
+        return ret;
+    }
+    inline int query(int xl, int xr, int yl, int yr) {
+		int ret = query(xr, yr);
+		add(ret, MOD-query(xl-1, yr));
+		add(ret, MOD-query(xr, yl-1));
+		add(ret, query(xl-1, yl-1));
+		return ret;
+    }
+} DP[MX][4];
+
+int main() {
+	if (fopen("in", "r")) freopen("in", "r", stdin), freopen("out", "w", stdout);
+	cin.tie(0)->sync_with_stdio(0);
+
+	int N; cin >> N;
+	for (int i = 0; i < N; ++i) cin >> S[i];
+
+	int ans = 0;
+	for (int i = 0; i < N; ++i) {
+		for (int a = 0; a < N; ++a) {
+			for (int b = a; b < N; ++b) {
+				if (S[i][b] != 'G') break;
+				
+				int sum = 1;
+				add(sum, DP[i][0].query(a, b, a, b));
+				DP[i+1][0].update(a, b, sum);
+				add(ans, sum);
+
+				sum = DP[i][1].query(a, b, b, N-1);
+				add(sum, DP[i][0].query(a, b, b+1, N-1));
+				DP[i+1][1].update(a, b, sum);
+				add(ans, sum);
+
+				sum = DP[i][2].query(0, a, a, b);
+				add(sum, DP[i][0].query(0, a-1, a, b));
+				DP[i+1][2].update(a, b, sum);
+				add(ans, sum);
+
+				sum = DP[i][3].query(0, a, b, N-1);
+				add(sum, DP[i][0].query(0, a-1, b+1, N-1));
+				add(sum, DP[i][1].query(0, a-1, b, N-1));
+				add(sum, DP[i][2].query(0, a, b+1, N-1));
+				DP[i+1][3].update(a, b, sum);
+				add(ans, sum);
+			}
+		}
+	}
+	cout << ans%MOD;
+}