init commit

lectures/t.cpp

@@ -0,0 +1,72 @@
+#include <iostream>
+#include <vector>
+#include <map>
+#include <set>
+#include <string>
+#include <algorithm>
+#include <fstream>
+
+int main() {
+    std::map<int, std::map<char, int>> trans;
+    std::set<int> accept_states;
+    int init_state = -1;
+
+    std::ifstream Input("noMore.in");
+    std::string str;
+    while (std::getline(Input, str)) {
+        if (str.empty()) break;
+        if (str.find("[[") != std::string::npos) {
+            int state;
+            sscanf(str.c_str(), "[[%d]]", &state);
+            accept_states.insert(state);
+            if (init_state == -1) {
+                init_state = state;
+            }
+        } else if (std::count(str.begin(), str.end(), '[') == 2) {
+            int left_state, right_state;
+            char symbol;
+            sscanf(str.c_str(), "[%d] %c [%d]", &left_state, &symbol, &right_state);
+            if (init_state == -1) {
+                init_state = left_state;
+            }
+            trans[left_state][symbol] = right_state;
+        } else {
+            int state;
+            sscanf(str.c_str(), "[%d]", &state);
+            if (init_state == -1) {
+                init_state = state;
+            }
+        }
+    }
+
+    int N;
+    Input >> N;
+
+    std::vector<std::map<int, size_t>> dp(N + 1);
+    dp[0][init_state] = 1;
+
+    for (int k = 1; k <= N; ++k) {
+        for (auto& [state, count] : dp[k - 1]) {
+            for (auto& [symbol, right_state] : trans[state]) {
+                dp[k][right_state] += count;
+            }
+        }
+    }
+
+    size_t ans = 0;
+    for (int k = 0; k <= N; ++k) {
+        for (auto& [state, count] : dp[k]) {
+            if (accept_states.count(state)) {
+                ans += count;
+            }
+        }
+    }
+
+    std::ofstream Output("noMore.out");
+    Output << ans << std::endl;
+
+    Output.close();
+    Input.close();
+
+    return 0;
+}