some programs!!

cs101/dh_00_16_swap_bits.cpp

@@ -0,0 +1,86 @@
+#include <cstring>
+#include <iostream>
+
+constexpr size_t MAX_N = 201;
+int n, evaluation_value, original_evaluation_value;
+bool bits[MAX_N], original_bits[MAX_N], target_bits[MAX_N];
+
+std::ostream& print_bits(const bool* bits_list = bits, std::ostream& os = std::clog) {
+    for (int i = 0; i < n; i++) {
+        os << (bits_list[i] ? 1 : 0);
+    }
+    return os;
+}
+
+void swap_bits(int i, int j) {
+    if (bits[i] != target_bits[i]) { evaluation_value--; }
+    if (bits[j] != target_bits[j]) { evaluation_value--; }
+    std::swap(bits[i], bits[j]);
+    if (bits[i] != target_bits[i]) { evaluation_value++; }
+    if (bits[j] != target_bits[j]) { evaluation_value++; }
+}
+
+int evaluate() {
+    if (evaluation_value == 1) { return 1; }
+    return evaluation_value / 2;
+}
+
+bool dfs(int last_swap_pos = 0, int depth = 0, int target_depth = 0) {
+    const int h = evaluate();
+    if (h == 0) { return true; }
+    if (depth + h > target_depth) {
+        return false;
+    }
+    std::clog << "DEPTH=" << depth << "\th=" << h << "\t";
+    print_bits() << "\t";
+    print_bits(target_bits) << std::endl;
+    for (int i = 0; i < n - 1; i++) {
+        if (bits[i] == bits[i + 1]) { continue; }
+        if (i == last_swap_pos) { continue; }
+        if (bits[i] == target_bits[i] && bits[i + 1] == target_bits[i + 1]) { continue; }
+        if ((bits[i] == target_bits[i] || bits[i + 1] == target_bits[i + 1]) &&
+            (bits[i + 1] != target_bits[i] && bits[i] != target_bits[i + 1])) { continue; }
+        swap_bits(bits[i], bits[i + 1]);
+        if (dfs(i, depth + 1, target_depth)) { return true; }
+        swap_bits(bits[i], bits[i + 1]);
+    }
+    return false;
+}
+
+int ida_star() {
+    for (int target_depth = evaluate(); target_depth <= 2 * n; target_depth++) {
+        memcpy(bits, original_bits, n);
+        evaluation_value = original_evaluation_value;
+        std::clog << "target_depth:" << target_depth << std::endl;
+        if (dfs(-1, 0, target_depth)) {
+            return target_depth;
+        }
+    }
+    return -1;
+}
+
+bool init_evaluate() {
+    int original_sum = 0, target_sum = 0;
+    for (int i = 0; i < n; i++) {
+        original_sum += original_bits[i];
+        target_sum += target_bits[i];
+        original_evaluation_value += original_bits[i] != target_bits[i];
+    }
+    return original_sum == target_sum;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    std::cin >> n;
+    for (int i = 0; i < n; i++) { std::cin >> original_bits[i]; }
+    for (int i = 0; i < n; i++) { std::cin >> target_bits[i]; }
+    if (!init_evaluate()) {
+        std::cout << -1 << std::endl;
+        return 0;
+    }
+    std::cout << ida_star() << std::endl;
+
+    return 0;
+}