feat: added WA and TLE solutions to delete-and-earn problem, also wrote the tutorial file

delete-and-earn/src/TLE.cpp

@@ -0,0 +1,44 @@
+#include <bits/stdc++.h>
+
+typedef long long ll;
+using namespace std;
+
+int findMaxPoints(vector<int>& values, int i) {
+    if (i == 0) {
+        return values[0];
+    }
+    
+    if (i == 1) {
+        return max(values[0], values[1]);
+    }
+    
+    // findMaxPoints(values, i - 1) means you don't take values[i].
+    // findMaxPoints(values, i - 2) + values[i] means you take values[i].
+    // Then, the max points you can get is the larger one of the two cases.
+    return max(findMaxPoints(values, i - 1), findMaxPoints(values, i - 2) + values[i]);
+}
+
+int deleteAndEarn(vector<int>& nums) {
+    int maxValue = nums[0];
+    for (int i = 0; i < nums.size(); ++i) {
+        maxValue = max(maxValue, nums[i]);
+    }
+    
+    vector<int> values(maxValue + 1, 0);
+    for (int i = 0; i < nums.size(); ++i) {
+        values[nums[i]] += nums[i];
+    }
+    
+    return findMaxPoints(values, values.size() - 1);
+}
+
+int main()
+{
+    int n;
+    cin >> n;
+    vector<int> nums(n);
+    for (int i = 0; i < n; i++)
+        cin >> nums[i];
+    cout << deleteAndEarn(nums) << endl;
+    return 0;
+}

delete-and-earn/src/WA.cpp

@@ -0,0 +1,37 @@
+#include <bits/stdc++.h>
+
+typedef long long ll;
+using namespace std;
+
+int deleteAndEarn(vector<int> &nums)
+{
+    int sum = 0;
+    map<int, int> quantity;
+    for (int n : nums)
+    {
+        sum += n;
+        quantity[n]++;
+    }
+
+    int maxSum = INT_MIN;
+    for (const auto &pair : quantity)
+    {
+        int currentSum = sum, n = pair.first;
+        if (quantity.count(n - 1))
+            currentSum -= quantity[n - 1] * (n - 1);
+        if (quantity.count(n + 1))
+            currentSum -= quantity[n + 1] * (n + 1);
+        maxSum = max(maxSum, currentSum);
+    }
+    return maxSum;
+}
+int main()
+{
+    int n;
+    cin >> n;
+    vector<int> nums(n);
+    for (int i = 0; i < n; i++)
+        cin >> nums[i];
+    cout << deleteAndEarn(nums) << endl;
+    return 0;
+}