From 09798454779c68cbc09d3aa4ced06f4132db67d3 Mon Sep 17 00:00:00 2001
From: Ta180m
Date: Sat, 5 Oct 2019 23:46:58 -0500
Subject: Create cowbasic.cpp

---
 2017/US Open/Platinum/cowbasic.cpp | 107 +++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 2017/US Open/Platinum/cowbasic.cpp

diff --git a/2017/US Open/Platinum/cowbasic.cpp b/2017/US Open/Platinum/cowbasic.cpp
new file mode 100644
index 0000000..bf1343d
--- /dev/null
+++ b/2017/US Open/Platinum/cowbasic.cpp	
@@ -0,0 +1,107 @@
+#include <bits/stdc++.h>
+#define init_io(pname) ifstream cin((string)pname+".in"); ofstream cout((string)pname+".out"); ios_base::sync_with_stdio(false); cin.tie(NULL)
+#define FOR(i, a, b, in) for (int i = (a); i < (b); i += in)
+#define REP(i, a, b) for (int i = (a); i < (b); i++)
+#define RFOR(i, a, b, in) for (int i = (a) - 1; i >= (b); i -= in)
+#define RREP(i, a, b) for (int i = (a) - 1; i >= (b); i--)
+#define trav(a, x) for (auto& a : x)
+#define mp make_pair
+#define pb push_back
+#define f first
+#define s second
+#define lb lower_bound
+#define ub upper_bound
+#define sz(x) (int)x.size()
+#define all(x) begin(x), end(x)
+#define rsz resize
+#define mem(a, b) memset(a, (b), sizeof(a))
+using namespace std;
+typedef string str;
+typedef long long ll;
+typedef long double ld;
+typedef pair<int, int> ii; typedef pair<ll, ll> pl; typedef pair<ld, ld> pd;
+typedef vector<int> vi; typedef vector<ll> vl; typedef vector<ld> vd;
+typedef vector<ii> vii; typedef vector<pl> vpl; typedef vector<pd> vpd;
+constexpr auto INF = (int)1e9;
+constexpr auto LINF = (ll)1e18;
+constexpr auto MOD = 1000000007;
+
+typedef vector<vi> matrix;
+
+int d = 0;
+map<str, int> var; // Variables
+vector<str> program; // Program
+stack<int> loop_st; // Loop stack
+vector<matrix> mat_st; // Matrix stack
+
+void mult(matrix& A, matrix& B) { // B = A * B;
+	matrix res(d + 1, vi(d + 1, 0));
+	for (int i = 0; i <= d; i++) {
+		for (int j = 0; j <= d; j++) {
+			for (int k = 0; k <= d; k++) {
+				res[i][j] = ((ll)A[i][k] * (ll)B[k][j] + res[i][j]) % MOD;
+			}
+		}
+	}
+	B = res;
+}
+
+void pow(matrix& A, int n) { // A ^ n
+	matrix res(d + 1, vi(d + 1, 0));
+	for (int i = 0; i <= d; i++) res[i][i] = 1;
+	while (n) {
+		if (n % 2 == 1) mult(A, res);
+		mult(A, A);
+		n /= 2;
+	}
+	A = res;
+}
+
+int main() {
+	init_io("cowbasic");
+
+	str input;
+	while (getline(cin, input)) program.push_back(input);
+
+	for (auto& line : program) { // Record variables
+		stringstream ss(line);
+		str n; ss >> n;
+		if (islower(n[0]) && var.find(n) == var.end()) var[n] = d++;
+	}
+
+	mat_st.push_back({});
+	mat_st.back().resize(d + 1, vi(d + 1, 0));
+	for (int i = 0; i <= d; i++) mat_st.back()[i][i] = 1;
+	for (auto& line : program) { // Process each line
+		stringstream ss(line);
+		str n; ss >> n;
+		if (islower(n[0])) { // Variable assignment
+			matrix M(d + 1, vi(d + 1, 0));
+			for (int i = 0; i <= d; i++) {
+				if (i != var[n]) M[i][i] = 1;
+			}
+			str tmp;
+			while (ss >> tmp) {
+				if (islower(tmp[0])) M[var[n]][var[tmp]]++;
+				else if (isdigit(tmp[0])) M[var[n]][d] += stoi(tmp);
+			}
+			mult(M, mat_st.back());
+		}
+		else if (isdigit(n[0])) { // Begin loop
+			mat_st.push_back({});
+			mat_st.back().resize(d + 1, vi(d + 1, 0));
+			for (int i = 0; i <= d; i++) mat_st.back()[i][i] = 1;
+			loop_st.push(stoi(n));
+		}
+		else if (n[0] == '}') { // End loop
+			pow(mat_st.back(), loop_st.top());
+			mult(mat_st.back(), mat_st[mat_st.size() - 2]);
+			mat_st.pop_back();
+			loop_st.pop();
+		}
+		else { // Return
+			ss >> n;
+			cout << mat_st.back()[var[n]][d] << endl;
+		}
+	}
+}
-- 
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