feat&bugfix: find real leetcode_235

Signed-off-by: Certseeds <51754303+Certseeds@users.noreply.github.com>
Certseeds · Feb 25, 2024 · cd55d11 · cd55d11
1 parent 0aa479c
commit cd55d11
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Showing 7 changed files with 199 additions and 129 deletions.
diff --git a/algorithm/tree/CMakeLists.txt b/algorithm/tree/CMakeLists.txt
@@ -13,7 +13,7 @@ LIST(APPEND leetcode_order 590 617 654 669 700)
 LIST(APPEND leetcode_order 701 144 145 102 101)
 LIST(APPEND leetcode_order 112 235 653 so_32 so_26)
 LIST(APPEND leetcode_order 113 426 so_54 114 230)
-LIST(APPEND leetcode_order 236 543 199 814 872)
+LIST(APPEND leetcode_order unknown 543 199 814 872)
 LIST(APPEND leetcode_order 894 897 938 965 993)
 LIST(APPEND leetcode_order 1008 1022 1038 1104 1261)
 LIST(APPEND leetcode_order 1302 1315 1325 1367 1372)

diff --git a/algorithm/tree/leetcode_235.cpp b/algorithm/tree/leetcode_235.cpp
@@ -2,29 +2,98 @@
 /*
 CS203_DSAA_template
 
-Copyright (C) 2020-2023 nanoseeds
+Copyright (C) 2020-2024 nanoseeds
 
 */
 #include "leetcode_235_test.hpp"
-#include "traverse.cpp"
+#include <unordered_map>
 
+// in cn, it is https://leetcode.cn/problems/lowest-common-ancestor-of-a-binary-search-tree
+// in us, it same with cn. it is https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree
+// why it's named _236 and where did the origin 235 come from ?
 namespace leetcode_235 {
-using namespace Tree_Traverse;
-
-bool leetcode_235::findTarget(TreeNode *root, int k) {
-    vector<int32_t> targets{};
-    const auto func = [&targets](const TreeNode *tn) -> void { targets.push_back(tn->val); };
-    iter::in(root, func);
-    for (size_t ll{0}, rr{targets.size() - 1}; ll < rr;) {
-        const auto sum = targets[ll] + targets[rr];
-        if (sum == k) {
-            return true;
-        } else if (sum > k) {
-            --rr;
-        } else if (sum < k) {
-            ++ll;
+using std::unordered_map;
+
+const TreeNode *leetcode_235::lowestCommonAncestorV2(TreeNode *root,
+                                                     TreeNode *p, TreeNode *q) {
+    // first, visit the p node, find it's parent-link
+    // then, visit the q node and match it's parents one by one.
+    if (root->val == p->val || root->val == q->val){
+        return root;
+    }
+    unordered_map<TreeNode*, int32_t> node_to_depth{};
+    int32_t depth{1};
+    for(TreeNode* base{root};base != nullptr && base->val != p->val;depth++ ) {
+        node_to_depth[base] = depth;
+        if (base->val > p->val) {
+            base = base->left;
+        } else if (base->val < p->val) {
+            base = base->right;
+        }
+    }
+    node_to_depth[p] = depth;
+    TreeNode* will_return{nullptr};
+    depth = 0;
+    for(TreeNode* base{root};base != nullptr && base->val != q->val;) {
+        if (node_to_depth.count(base) != 0 && node_to_depth[base] > depth) {
+            will_return = base;
+            depth = node_to_depth[base];
+        }
+        if (base->val > q->val) {
+            base = base->left;
+        } else if (base->val <q->val) {
+            base = base->right;
         }
     }
-    return false;
+    if (node_to_depth.count(q) != 0 && node_to_depth[q] > depth) {
+        will_return = q;
+    }
+    return will_return;
 }
+
+bool nodeHadValue(unordered_map<TreeNode *, uint8_t> &umap, TreeNode *base, int32_t value) {
+    if (base == nullptr) {
+        return false;
+    }
+    if (umap.count(base) != 0) {
+        return umap.at(base);
+    }
+    if (base->val == value) {
+        umap[base] = true;
+        return true;
+    }
+    const auto will_return = nodeHadValue(umap, base->left, value) || nodeHadValue(umap, base->right, value);
+    umap[base] = will_return;
+    return will_return;
+}
+
+const TreeNode *
+leetcode_235::lowestCommonAncestor(const TreeNode *root, const TreeNode *const p, const TreeNode *const q) {
+    if (root == nullptr) {
+        return nullptr;
+    }
+    for (unordered_map<TreeNode *, uint8_t> pmap, qmap; root != nullptr;) {
+        if (root->val == p->val) {
+            return p;
+        } else if (root->val == q->val) {
+            return q;
+        }
+        const auto pleft = nodeHadValue(pmap, root->left, p->val);
+        const auto pright = nodeHadValue(pmap, root->right, p->val);
+
+        const auto qleft = nodeHadValue(qmap, root->left, q->val);
+        const auto qright = nodeHadValue(qmap, root->right, q->val);
+        if (pleft && qright) {
+            return root;
+        } else if (pright && qleft) {
+            return root;
+        } else if (pleft && qleft) {
+            root = root->left;
+        } else {
+            root = root->right;
+        }
+    }
+    return nullptr;
+}
+
 }
diff --git a/algorithm/tree/leetcode_235_test.hpp b/algorithm/tree/leetcode_235_test.hpp
@@ -7,7 +7,6 @@ Copyright (C) 2020-2023 nanoseeds
 */
 //@Tag tree
 //@Tag 树
-//@Plan 数据结构入门 Day14
 #ifndef CS203_DSAA_TEMPLATE_ALGORITHM_TREE_LEETCODE_235_TEST_HPP
 #define CS203_DSAA_TEMPLATE_ALGORITHM_TREE_LEETCODE_235_TEST_HPP
 
@@ -21,21 +20,53 @@ Copyright (C) 2020-2023 nanoseeds
 namespace leetcode_235 {
 
 using TreeNode = TREE_NODE::TreeNode<int32_t>;
-
-struct leetcode_235 {
-    static bool findTarget(TreeNode *root, int k);
+namespace leetcode_235 {
+    const TreeNode *lowestCommonAncestor(const TreeNode *root, const TreeNode *p, const TreeNode *q);
+    const TreeNode *lowestCommonAncestorV2(TreeNode *root, TreeNode *p, TreeNode *q);
 };
 
+
 using TreeNodeLink = TREE_NODE::TreeNodeLink<int32_t>;
+using TREE_NODE::numToTree;
 
 TEST_CASE("test_case 1 [test_235]", "[test_235]") {
+    const TreeNodeLink input{6,
+                             2, 8,
+                             0, 4, 7, 9,
+                             TreeNode::No, TreeNode::No, 3, 5};
+    const TreeNode p{2}, q{8};
+    static constexpr const auto result{6};
+    CHECK(result == leetcode_235::lowestCommonAncestor(input[0], &p, &q)->val);
+    CHECK(result == leetcode_235::lowestCommonAncestorV2(input[0], input[1], input[2])->val);
+}
+TEST_CASE("test_case 2 [test_235]", "[test_235]") {
+    const TreeNodeLink input{2,
+                             1};
+    const TreeNode p{1}, q{2};
+    static constexpr const auto result{2};
+    CHECK(result == leetcode_235::lowestCommonAncestor(input[0], &p, &q)->val);
+    CHECK(result == leetcode_235::lowestCommonAncestorV2(input[0], input[0], input[1])->val);
+}
+
+TEST_CASE("test_case 3 [test_235]", "[test_235]") {
+    const TreeNodeLink input{6,
+                             2, 8,
+                             0, 4, 7, 9,
+                             TreeNode::No, TreeNode::No, 3, 5};
+    TreeNode p{2}, q{4};
+    static constexpr const auto result{2};
+    CHECK(result == leetcode_235::lowestCommonAncestor(input[0], &p, &q)->val);
+    CHECK(result == leetcode_235::lowestCommonAncestorV2(input[0], input[1], input[4])->val);
+}
+TEST_CASE("test_case 4 [test_235]", "[test_235]") {
     const TreeNodeLink input{5,
-                                3, 6,
-                                2, 4, TreeNode::No, 7,
-                                TreeNode::No, TreeNode::No, TreeNode::No, TreeNode::No, TreeNode::No, TreeNode::No,
-                                TreeNode::No, TreeNode::No};
-    static constexpr const auto target{9};
-    CHECK(leetcode_235::findTarget(input[0], target));
+                             3, 6,
+                             2, 4,TreeNode::No, TreeNode::No,
+                             1};
+    TreeNode p{1}, q{3};
+    static constexpr const auto result{3};
+    CHECK(result == leetcode_235::lowestCommonAncestor(input[0], &p, &q)->val);
+    CHECK(result == leetcode_235::lowestCommonAncestorV2(input[0], input[7], input[1])->val);
 }
 }
 #endif //CS203_DSAA_TEMPLATE_ALGORITHM_TREE_LEETCODE_235_TEST_HPP
diff --git a/algorithm/tree/leetcode_236.cpp b/algorithm/tree/leetcode_236.cpp
diff --git a/algorithm/tree/leetcode_236_test.hpp b/algorithm/tree/leetcode_236_test.hpp
diff --git a/algorithm/tree/leetcode_unknown.cpp b/algorithm/tree/leetcode_unknown.cpp
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+/*
+CS203_DSAA_template
+
+Copyright (C) 2020-2023 nanoseeds
+
+*/
+#include "leetcode_unknown_test.hpp"
+#include "traverse.cpp"
+
+namespace leetcode_unknown {
+using namespace Tree_Traverse;
+
+bool leetcode_235::findTarget(TreeNode *root, int k) {
+    vector<int32_t> targets{};
+    const auto func = [&targets](const TreeNode *tn) -> void { targets.push_back(tn->val); };
+    iter::in(root, func);
+    for (size_t ll{0}, rr{targets.size() - 1}; ll < rr;) {
+        const auto sum = targets[ll] + targets[rr];
+        if (sum == k) {
+            return true;
+        } else if (sum > k) {
+            --rr;
+        } else if (sum < k) {
+            ++ll;
+        }
+    }
+    return false;
+}
+}
diff --git a/algorithm/tree/leetcode_unknown_test.hpp b/algorithm/tree/leetcode_unknown_test.hpp
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+/*
+CS203_DSAA_template
+
+Copyright (C) 2020-2023 nanoseeds
+
+*/
+//@Tag tree
+//@Tag 树
+//@Plan 数据结构入门 Day14
+#ifndef CS203_DSAA_TEMPLATE_ALGORITHM_TREE_LEETCODE_UNKNOWN_TEST_HPP
+#define CS203_DSAA_TEMPLATE_ALGORITHM_TREE_LEETCODE_UNKNOWN_TEST_HPP
+
+#include <catch_main.hpp>
+#include <cstdint>
+#include <cstddef>
+#include <tree/treenode.hpp>
+#include <tree/treenode_link.hpp>
+#include <vector>
+
+namespace leetcode_unknown {
+
+using TreeNode = TREE_NODE::TreeNode<int32_t>;
+
+struct leetcode_unknown {
+    static bool findTarget(TreeNode *root, int k);
+};
+
+using TreeNodeLink = TREE_NODE::TreeNodeLink<int32_t>;
+
+TEST_CASE("test_case 1 [test_235]", "[test_235]") {
+    const TreeNodeLink input{5,
+                                3, 6,
+                                2, 4, TreeNode::No, 7,
+                                TreeNode::No, TreeNode::No, TreeNode::No, TreeNode::No, TreeNode::No, TreeNode::No,
+                                TreeNode::No, TreeNode::No};
+    static constexpr const auto target{9};
+    CHECK(leetcode_unknown::findTarget(input[0], target));
+}
+}
+#endif //CS203_DSAA_TEMPLATE_ALGORITHM_TREE_LEETCODE_UNKNOWN_TEST_HPP