complete 7604.cpp 1267.rs 8760.rs

storage/zeta/cpp/completed/7604.cpp

@@ -0,0 +1,95 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+#define let auto
+
+void fastio() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(nullptr);
+}
+
+auto transform_to_postorder(vector<char> preorder, vector<char> inorder, vector<char> &postorder) -> bool {
+    if (preorder.size() == 0) {
+        return true;
+    }
+
+    let root = preorder[0];
+
+    if (preorder.size() == 1) {
+        if (preorder[0] == inorder[0]) {
+            postorder[0] = root;
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    let find = inorder.begin();
+
+    for (find = inorder.begin(); find != inorder.end(); find++) {
+        if (*find == root) {
+            break;
+        }
+    }
+
+    if (find == inorder.end()) {
+        return false;
+    }
+
+    let left_subtree_inorder = vector<char>(inorder.begin(), find);
+    let right_subtree_inorder = vector<char>(find + 1, inorder.end());
+
+    let left_size = left_subtree_inorder.size();
+    let right_size = right_subtree_inorder.size();
+
+    let left_subtree_preorder = vector<char>(preorder.begin() + 1, preorder.begin() + 1 + left_size);
+    let right_subtree_preorder = vector<char>(preorder.begin() + 1 + left_size, preorder.end());
+
+    // propagate
+    let left_sub_post = vector<char>(left_subtree_inorder.size());
+    let right_sub_post = vector<char>(right_subtree_inorder.size());
+    let sig_left = transform_to_postorder(
+            left_subtree_preorder, left_subtree_inorder, left_sub_post);
+    let sig_right = transform_to_postorder(
+            right_subtree_preorder, right_subtree_inorder, right_sub_post);
+
+    if (sig_left == false || sig_right == false) {
+        return false;
+    }
+
+    std::copy(
+            left_sub_post.begin(), left_sub_post.end(), postorder.begin());
+    std::copy(
+            right_sub_post.begin(), right_sub_post.end(), postorder.begin() + left_sub_post.size());
+
+    postorder[postorder.size() - 1] = root;
+    return true;
+}
+
+auto main() -> int {
+    fastio();
+
+    string pre_str, in_str;
+
+    while (cin >> pre_str && pre_str != "#") {
+        cin >> in_str;
+
+        vector<char> preorders(pre_str.begin(), pre_str.end());
+        vector<char> inorders(in_str.begin(), in_str.end());
+
+        vector<char> postorders(preorders.size());
+
+        if (transform_to_postorder(preorders, inorders, postorders)) {
+            for (let c: postorders) {
+                cout << c;
+            }
+            cout << "\n";
+        } else {
+            cout << "Invalid tree\n";
+        }
+    }
+
+    return 0;
+}