P9752 [CSP-S 2023] 密码锁

https://www.luogu.com.cn/record/134755461

Luogu/P9752/P9752.cpp

@@ -0,0 +1,78 @@
+#include <iostream>
+#include <array>
+#include <set>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 10,
+          M = 5;
+
+int n, ans;
+std::array<int, M> a[N];
+std::set<std::array<int, M>> set_pre;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        for (int j = 0; j < M; j++) {
+            cin >> a[i][j];
+        }
+    }
+
+    for (int i = 1; i <= n; i++) {
+        std::set<std::array<int, M>> set_now;
+
+        // Type 1: Only one element is different.
+        for (int j = 0; j < M; j++) {
+            std::array<int, M> t = a[i];
+
+            for (int k = 0; k < 10; k++) {
+                t[j] = (a[i][j] + k) % 10;
+
+                if (t[j] != a[i][j]) {
+                    set_now.emplace(t);
+                }
+            }
+        }
+
+        // Type 2: Two adjacent elements are different.
+        for (int j = 0; j + 1 < M; j++) {
+            std::array<int, M> t = a[i];
+
+            for (int k = 0; k < 10; k++) {
+                t[j] = (a[i][j] + k) % 10;
+                t[j + 1] = (a[i][j + 1] + k) % 10;
+
+                if (t[j] != a[i][j]) {
+                    set_now.emplace(t);
+                }
+            }
+        }
+
+        if (i == 1) {
+            ans = set_now.size();
+            set_pre = set_now;
+        } else {
+            std::set<std::array<int, M>> set;
+
+            for (auto o : set_pre) {
+                if (set_now.count(o)) {
+                    set.emplace(o);
+                }
+            }
+
+            ans = set.size();
+            set_pre = set;
+        }
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}