did my first leetcode hard, some greey problems, and string problems

Author: Github11200

Solutions/Leetcode Solutions/easy/ransomNote.cpp

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+#include "../../../helperFunctions.h"
+
+using namespace std;
+
+/******************************************
+  Link: https://leetcode.com/problems/ransom-note/description/
+  Runtime: 73.37%
+  Memory: 53.74%
+******************************************/
+
+bool ransomNote(string ransomNote, string magazine)
+{
+  unordered_map<char, int> letterCounts;
+  for (int i = 0; i < ransomNote.size(); ++i)
+    ++letterCounts[ransomNote[i]];
+
+  for (int i = 0; i < magazine.size(); ++i)
+  {
+    if (letterCounts.count(magazine[i]))
+    {
+      --letterCounts[magazine[i]];
+      if (letterCounts[magazine[i]] == 0)
+        letterCounts.erase(magazine[i]);
+    }
+  }
+
+  return letterCounts.empty();
+}
+
+int main()
+{
+  cout << ransomNote("aa", "aab") << endl;
+  return 0;
+}

Solutions/Leetcode Solutions/easy/reverseVowelsOfAString.cpp

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+#include "../../../helperFunctions.h"
+
+using namespace std;
+
+/******************************************
+  Link: https://leetcode.com/problems/reverse-vowels-of-a-string/description/
+  Runtime: 100.00%
+  Memory: 82.35%
+******************************************/
+
+string reverseVowelsOfAString(string s)
+{
+  int i = 0;
+  int j = s.size() - 1;
+
+  while (i < j)
+  {
+    char firstLetter = s[i];
+    char secondLetter = s[j];
+    bool shouldSwap = true;
+    if (!(firstLetter == 'a' || firstLetter == 'A' || firstLetter == 'e' || firstLetter == 'E' || firstLetter == 'i' || firstLetter == 'I' || firstLetter == 'o' || firstLetter == 'O' || firstLetter == 'u' || firstLetter == 'U'))
+    {
+      ++i;
+      shouldSwap = false;
+    }
+    if (!(secondLetter == 'a' || secondLetter == 'A' || secondLetter == 'e' || secondLetter == 'E' || secondLetter == 'i' || secondLetter == 'I' || secondLetter == 'o' || secondLetter == 'O' || secondLetter == 'u' || secondLetter == 'U'))
+    {
+      --j;
+      shouldSwap = false;
+    }
+    if (shouldSwap)
+    {
+      swap(s[i], s[j]);
+      ++i;
+      --j;
+    }
+  }
+
+  return s;
+}
+
+int main()
+{
+  cout << reverseVowelsOfAString("IceCreAm") << endl;
+  return 0;
+}

Solutions/Leetcode Solutions/hard/candy.cpp

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+#include "../../../helperFunctions.h"
+
+using namespace std;
+
+/******************************************
+  Link: https://leetcode.com/problems/candy/description/
+  Runtime: 100.0%
+  Memory: 25.41%
+******************************************/
+
+int candy(vector<int> &ratings)
+{
+  vector<int> candies(ratings.size(), 1);
+  for (int i = 0; i < ratings.size(); ++i)
+  {
+    if (i > 0 && ratings[i] < ratings[i - 1] && candies[i - 1] <= candies[i])
+      candies[i - 1] = candies[i] + 1;
+    if (i < ratings.size() - 1 && ratings[i] < ratings[i + 1] && candies[i + 1] <= candies[i])
+      candies[i + 1] = candies[i] + 1;
+  }
+
+  for (int i = ratings.size() - 1; i >= 0; --i)
+  {
+    if (i > 0 && ratings[i] < ratings[i - 1] && candies[i - 1] <= candies[i])
+      candies[i - 1] = candies[i] + 1;
+    if (i < ratings.size() - 1 && ratings[i] < ratings[i + 1] && candies[i + 1] <= candies[i])
+      candies[i + 1] = candies[i] + 1;
+  }
+
+  int sum = 0;
+  for (int i = 0; i < candies.size(); ++i)
+    sum += candies[i];
+  return sum;
+}
+
+int main()
+{
+  vector<int> nums1({1, 0, 2});
+  cout
+      << candy(nums1) << endl;
+  return 0;
+}

Solutions/Leetcode Solutions/medium/gasStation.cpp

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+#include "../../../helperFunctions.h"
+
+using namespace std;
+
+/******************************************
+  Link: https://leetcode.com/problems/gas-station/description/
+  Runtime: 100.0%
+  Memory: 72.09%
+******************************************/
+
+int gasStation(vector<int> &gas, vector<int> &cost)
+{
+  int gasSum = 0;
+  int costSum = 0;
+  for (int i = 0; i < gas.size(); ++i)
+  {
+    gasSum += gas[i];
+    costSum += cost[i];
+  }
+
+  if (gasSum < costSum)
+    return -1;
+
+  int start = 0;
+  int sum = 0;
+  for (int i = 0; i < gas.size(); ++i)
+  {
+    sum += gas[i] - cost[i];
+    if (sum < 0)
+    {
+      sum = 0;
+      start = i + 1;
+    }
+  }
+  return start;
+}
+
+int main()
+{
+  vector<int> nums1({5, 1, 2, 3, 4});
+  vector<int> nums2({4, 4, 1, 5, 1});
+  cout << gasStation(nums1, nums2) << endl;
+  return 0;
+}

Solutions/Leetcode Solutions/medium/houseRobber.cpp

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+#include "../../../helperFunctions.h"
+
+using namespace std;
+
+/******************************************
+  Link: https://leetcode.com/problems/house-robber/description/
+  Runtime: 100.0%
+  Memory: 20.20%
+******************************************/
+
+int rob(vector<int> &nums)
+{
+  if (nums.size() == 1)
+    return nums[0];
+  else if (nums.size() == 2)
+    return max(nums[0], nums[1]);
+
+  vector<int> houseValues(nums.size());
+  houseValues[0] = nums[0];
+  houseValues[1] = nums[1];
+  for (int i = 2; i < houseValues.size(); ++i)
+  {
+    int max1 = -1;
+    for (int j = 2; i - j >= 0; ++j)
+      max1 = max(max1, houseValues[i - j] + nums[i]);
+    houseValues[i] = max(houseValues[i - 1], max1);
+  }
+
+  return houseValues[houseValues.size() - 1];
+}
+
+int main()
+{
+  vector<int> testing({1, 2, 3, 1});
+  cout << rob(testing) << endl;
+
+  return 0;
+}

Solutions/Leetcode Solutions/medium/longestSubstringWithoutRepeatingCharacters.cpp

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+#include <bits/stdc++.h>
+
+using namespace std;
+
+/******************************************
+  Link: https://leetcode.com/problems/longest-substring-without-repeating-characters/description/
+  Runtime: 551 ms
+  Memory: 144.45 mb
+******************************************/
+
+int lengthOfLongestSubstring(string s)
+{
+  int longest = -1;
+  int currentLength = 0;
+  unordered_map<char, int> previousCharacters;
+  for (int i = 0; i < s.size(); ++i)
+  {
+    if (previousCharacters.count(s[i]) == 0)
+    {
+      previousCharacters[s[i]] = i;
+      ++currentLength;
+    }
+    else
+    {
+      i = previousCharacters[s[i]];
+      longest = max(longest, currentLength);
+      currentLength = 0;
+      previousCharacters.clear();
+    }
+  }
+
+  longest = max(longest, currentLength);
+  return longest;
+}
+
+int main()
+{
+  cout << lengthOfLongestSubstring("dvdf") << endl;
+  return 0;
+}

Solutions/Leetcode Solutions/medium/stringToInteger

@@ -0,0 +1,46 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+/******************************************
+  Link:
+  Runtime:
+  Memory:
+******************************************/
+
+int stringToInteger(string s)
+{
+  int result = NULL;
+  vector<int> digits;
+  int sign = 1;
+  for (int i = 0; i < s.size(); ++i)
+  {
+    if (s[i] == ' ')
+      continue;
+
+    // It's a negative
+    if (int(s[i]) == 45)
+      sign *= -1;
+    // It's a positive
+    else if (int(s[i]) == 43)
+      sign *= 1;
+    else if (int(s[i]) >= 48 && int(s[i]) <= 57)
+      digits.push_back(s[i] - '0');
+
+    // Not an integer
+    if (int(s[i]) < 48 || int(s[i]) > 57 || (i < s.size() - 1 && (int(s[i + 1]) < 48 || int(s[i + 1]) > 57)))
+      break;
+  }
+
+  result = 0;
+  for (int i = digits.size() - 1; i >= 0; --i)
+    result += digits[i] * pow(10, digits.size() - 1 - i);
+
+  return result * sign;
+}
+
+int main()
+{
+  cout << stringToInteger("1337c0d3") << endl;
+  return 0;
+}