cleanup cpp files

Author: charliesbot

cpp/0001_two_sum/0001_two_sum.cc

@@ -1,8 +1,25 @@
+#include <unordered_map>
 #include <vector>
 
+using std::unordered_map;
 using std::vector;
 
 class Solution {
 public:
-  vector<int> twoSum(vector<int> &nums, int target);
+  vector<int> twoSum(vector<int> &nums, int target) {
+
+    unordered_map<int, int> umap;
+    for (int i = 0; i < nums.size(); i++) {
+      const int current = nums[i];
+
+      if (umap.count(current) > 0) {
+        return {i, umap[current]};
+      }
+
+      const int diff = target - nums[i];
+      umap[diff] = i;
+    }
+
+    return {};
+  }
 };

cpp/0001_two_sum/0001_two_sum.h

@@ -0,0 +1,32 @@
+#include <algorithm>
+#include <string>
+#include <unordered_map>
+
+using ::std::max;
+using ::std::string;
+using ::std::unordered_map;
+
+class Solution {
+public:
+  int lengthOfLongestSubstring(string s) {
+    unordered_map<char, int> hash;
+    int length = 0;
+    int max_length = 0;
+    int start = 0;
+
+    for (int i = 0; i < s.length(); i++) {
+      const char &letter = s[i];
+
+      if (hash.find(letter) != hash.end() && hash[letter] >= start) {
+        start = hash[letter] + 1;
+        length = i - start;
+      }
+
+      length++;
+      hash[letter] = i;
+      max_length = max(length, max_length);
+    }
+
+    return max_length;
+  }
+};

cpp/0003_longest_substring_without_repeating_characters/0003_longest_substring_without_repeating_characters.h

@@ -0,0 +1,29 @@
+#include "0003_longest_substring_without_repeating_characters.h"
+#include <gtest/gtest.h>
+#include <string>
+
+using ::std::string;
+
+TEST(LengthOfLongestSubstring, Example1) {
+  string s = "abcabcbb";
+
+  EXPECT_EQ(Solution().lengthOfLongestSubstring(s), 3);
+}
+
+TEST(LengthOfLongestSubstring, Example2) {
+  string s = "bbbbb";
+
+  EXPECT_EQ(Solution().lengthOfLongestSubstring(s), 1);
+}
+
+TEST(LengthOfLongestSubstring, Example3) {
+  string s = "pwwkew";
+
+  EXPECT_EQ(Solution().lengthOfLongestSubstring(s), 3);
+}
+
+TEST(LengthOfLongestSubstring, Example4) {
+  string s = "";
+
+  EXPECT_EQ(Solution().lengthOfLongestSubstring(s), 0);
+}

cpp/0003_longest_substring_without_repeating_characters/0003_longest_substring_without_repeating_characters_test.cc

@@ -1,9 +1,37 @@
-#include <stdio.h>
+#include <stack>
 #include <string>
+#include <unordered_map>
+
+using std::stack;
+using std::unordered_map;
 
 using std::string;
 
 class Solution {
 public:
-    bool isValid(string s);
+  bool isValid(string s) {
+    unordered_map<char, char> dict({{'(', ')'}, {'[', ']'}, {'{', '}'}});
+    stack<char> stack;
+
+    for (const char &letter : s) {
+      if (dict.find(letter) != dict.end()) {
+        stack.push(dict[letter]);
+        continue;
+      }
+
+      if (stack.empty()) {
+        return false;
+      }
+
+      const char &popped = stack.top();
+
+      if (letter != popped) {
+        return false;
+      }
+
+      stack.pop();
+    }
+
+    return stack.empty();
+  }
 };

cpp/0020_valid_parentheses/0020_valid_parentheses.cc

@@ -3,6 +3,33 @@
 using std::vector;
 
 class Solution {
+
+private:
+  void dfs(vector<vector<char>> &grid, size_t row, size_t column) {
+    if (row >= grid.size() || column >= grid[row].size() ||
+        grid[row][column] == '0') {
+      return;
+    }
+
+    grid[row][column] = '0';
+    dfs(grid, row + 1, column);
+    dfs(grid, row, column + 1);
+    dfs(grid, row - 1, column);
+    dfs(grid, row, column - 1);
+  }
+
 public:
-  int numIslands(vector<vector<char>> &grid);
-};
+  int numIslands(vector<vector<char>> &grid) {
+    int islands = 0;
+    for (int row = 0; row < grid.size(); row++) {
+      for (int column = 0; column < grid[row].size(); column++) {
+        if (grid[row][column] == '1') {
+          islands++;
+          dfs(grid, row, column);
+        }
+      }
+    }
+
+    return islands;
+  }
+};

cpp/0020_valid_parentheses/0020_valid_parentheses.h

@@ -6,7 +6,7 @@ cc_library(
     hdrs=glob(["**/**/*.h"]),
     srcs = glob(
         ["**/**/*.cc"],
-        exclude = ["**/**/*_test.cc"]
+        exclude = ["**/**/*test.cc"]
     ),
     visibility = ["//visibility:public"],
 )