add solution to longest-increasing-subsequence problem

algorithms/CPlusPlus/Arrays/longest-increasing-subsequence.cpp

@@ -0,0 +1,26 @@
+// Given int array, return length of longest increasing subsequence
+//     Ex. nums = [10,9,2,5,3,7,101,18] -> 4, [2,3,7,101]
+//    Time: O(n^2)
+//     Space: O(n)
+#include <bits/stdc++.h>
+
+class Solution {
+public:
+    int lengthOfLIS(vector<int>& nums) {
+        int n = nums.size();
+        vector<int> dp(n, 1);
+        
+        int result = 1;
+        
+        for (int i = 1; i < n; i++) {
+            for (int j = 0; j < i; j++) {
+                if (nums[j] < nums[i]) {
+                    dp[i] = max(dp[i], dp[j] + 1);
+                }
+            }
+            result = max(result, dp[i]);
+        }
+        
+        return result;
+    }
+};