GH-169: Solve leetcode 142 (#170)

Author: rain1024

concepts/cpp/set.md

@@ -46,6 +46,11 @@ int main() {
     cout << x << endl;
   }
 
+  // Check if the element with value 5 is in the set
+  if (s.find(5) != s.end()) {
+    cout << "5 is in the set" << endl;
+  }
+
   return 0;
 }
 ```
@@ -126,6 +131,7 @@ Set Difference: B - A
 |----------------|-----------------|-----------------|
 | Insert         | insert          | $$O(log n)$$    |
 | Delete         | erase           | $$O(log n)$$    |
+| Find           | find            | $$O(log n)$$    |
 | Union          | set_union       | $$O(m log n)$$  |
 | Intersection   | set_intersection| $$O(m log n)$$  |
 | Difference     | set_difference  | $$O(m log n)$$  |

problems/leetcode142/.gitignore

@@ -0,0 +1 @@
+solution

problems/leetcode142/README.md

@@ -0,0 +1,19 @@
+# Leetcode Problem 
+
+## Usage
+
+Run program with an example
+
+```
+bazel run src/main:solution < data/1.in
+```
+
+Test program
+
+```
+# Run all tests
+bazel test --test_output=all tests:solution_test
+bazel test --test_output=all --cache_test_results=no tests:solution_test
+# Run test with pecific test id
+bazel test --test_output=all tests:solution_test --test_arg=1
+```

problems/leetcode142/data/1.in

@@ -0,0 +1,3 @@
+4
+3 2 0 -4
+1

problems/leetcode142/data/1.out

@@ -0,0 +1 @@
+tail connects to node index 1

problems/leetcode142/data/2.in

@@ -0,0 +1,3 @@
+2
+1 2
+0

problems/leetcode142/data/2.out

@@ -0,0 +1 @@
+tail connects to node index 0

problems/leetcode142/data/3.in

@@ -0,0 +1,3 @@
+1
+1
+-1

problems/leetcode142/data/3.out

@@ -0,0 +1 @@
+NULL

problems/leetcode142/problem_infos.json

@@ -0,0 +1,9 @@
+{
+  "name": "Leetcode 78. Subsets",
+  "link": "https://leetcode.com/problems/subsets/",
+  "tags": [
+    "Array",
+    "Backtracking",
+    "Bit Manipulation"
+  ]
+}

problems/leetcode142/src/main/BUILD

@@ -0,0 +1,7 @@
+load("@rules_cc//cc:defs.bzl", "cc_binary")
+
+cc_binary(
+    name = "solution",
+    srcs = ["solution.cpp", "solution.h"],
+    visibility = ["//visibility:public"],
+)

problems/leetcode142/src/main/solution.cpp

@@ -0,0 +1,53 @@
+#include "solution.h"
+
+#include <algorithm>
+#include <cmath>
+#include <iostream>
+#include <map>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+int main() {
+  ios::sync_with_stdio(false);
+  cin.tie(0);
+
+  int n;
+  cin >> n;
+
+  vector<ListNode*> vln(n);
+
+  int val;
+  for(int i=0; i<n; i++){
+    cin >> val;
+    vln[i] = new ListNode(val);
+  }
+  for (int i = 0; i < n-1; i++) {
+    vln[i]->next = vln[i + 1];
+  }
+
+  int tail;
+  cin >> tail;
+  if (tail != -1) {
+    vln[n - 1]->next = vln[tail];
+  }
+
+  ListNode* head = vln[0];
+
+  Solution solution;
+  ListNode* result = solution.detectCycle(head);
+
+  if (result == NULL) {
+    cout << "no cycle" << endl;
+  } else {
+    for(int i=0; i<n; i++){
+      if(vln[i] == result){
+        cout << "tail connects to node index " << i << endl;
+        break;
+      }
+    }
+  }
+
+  return 0;
+}

problems/leetcode142/src/main/solution.h

@@ -0,0 +1,41 @@
+#include <algorithm>
+#include <cmath>
+#include <map>
+#include <set>
+#include <stack>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+using namespace std;
+
+struct ListNode {
+  int val;
+  ListNode *next;
+  ListNode(int x) : val(x), next(NULL) {}
+};
+
+class Solution {
+ public:
+  ListNode *detectCycle(ListNode *head) {
+    ListNode *fast = head;
+    ListNode *slow = head;
+
+    while (fast && slow) {
+      if (!fast->next || !fast->next->next) {
+        return NULL;
+      }
+      fast = fast->next->next;
+      slow = slow->next;
+      if (fast == slow) {
+        break;
+      }
+    }
+
+    while (slow != head) {
+      slow = slow->next;
+      head = head->next;
+    }
+    return slow;
+  }
+};

problems/leetcode142/tests/BUILD

@@ -0,0 +1,11 @@
+load("@rules_cc//cc:defs.bzl", "cc_binary", "cc_test")
+
+cc_test(
+    name = "solution_test",
+    srcs = ["solution_test.cpp"],
+    deps = [
+      "//problems/codeforcesAA/src/main:solution",
+      "@com_google_googletest//:gtest_main",
+    ],
+    data = ["data"]
+)

problems/leetcode142/tests/solution_test.cpp

@@ -0,0 +1,97 @@
+#include <cstdlib>
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include "gtest/gtest.h"
+
+namespace fs = std::filesystem;
+
+using namespace std;
+
+std::string TEST_ID = "";
+
+vector<string> split(string s, string delimiter) {
+  size_t pos_start = 0, pos_end, delim_len = delimiter.length();
+  string token;
+  vector<string> res;
+
+  while ((pos_end = s.find(delimiter, pos_start)) != string::npos) {
+    token = s.substr(pos_start, pos_end - pos_start);
+    pos_start = pos_end + delim_len;
+    res.push_back(token);
+  }
+
+  res.push_back(s.substr(pos_start));
+  return res;
+}
+
+std::string GetHello(std::string_view in) {
+  if (in.size() == 0) {
+    return std::string("hello, word");
+  } else {
+    return std::string("Hello, ") + in.data();
+  }
+}
+
+string ReadFile(const std::string &filename) {
+  std::ifstream f(filename);
+  string s((std::istreambuf_iterator<char>(f)),
+           std::istreambuf_iterator<char>());
+  return s;
+}
+
+vector<string> RunProgram(string fileid) {
+  vector<string> v;
+  string program = "problems/codeforcesAA/src/main/solution";
+  string test_folder = "problems/codeforcesAA/tests/data/";
+  string command = program + " < " + test_folder + fileid + ".in > output.txt";
+  std::system(command.c_str());
+  string actual = ReadFile("output.txt");
+  string expectedOutputFile = test_folder + fileid + ".out";
+  string expected = ReadFile(expectedOutputFile);
+  v.push_back(actual);
+  v.push_back(expected);
+  return v;
+}
+
+TEST(RunTest, AllTestCases) {
+  if (TEST_ID != "") {
+    std::cout << "TEST_ID = " << TEST_ID << std::endl;
+  } else {
+    std::cout << "RUN ALL TESTS" << std::endl;
+  }
+
+  std::string test_data_folder = "problems/codeforcesAA/tests/data";
+  for (const auto &entry : fs::directory_iterator(test_data_folder)) {
+    string filename = split(entry.path(), "/").back();
+    vector<string> v = split(filename, ".");
+    string fileid = v[0];
+    string extension = v[1];
+    if (extension != "in"){
+      continue;
+    }
+    if (TEST_ID != ""){
+      if (fileid != TEST_ID){
+        continue;
+      }
+    }
+    // Run Test Case
+    vector<string> output = RunProgram(fileid);
+    string actual = output[0];
+    string expected = output[1];
+    string message = "❌ FAIL CASE: " + fileid;
+    ASSERT_EQ(actual, expected) << message;
+  }
+}
+
+int main(int argc, char **argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  if (argc == 2) {
+    TEST_ID = argv[1];
+  }
+  return RUN_ALL_TESTS();
+}