problems: add „Longest Increasing Subsequence“

Signed-off-by: Matej Focko <mfocko@redhat.com>

problems/longest-increasing-subsequence.rs

@@ -0,0 +1,18 @@
+use std::cmp::max;
+
+impl Solution {
+    pub fn length_of_lis(nums: Vec<i32>) -> i32 {
+        let mut dp = Vec::<i32>::new();
+        dp.resize(nums.len(), 1);
+
+        for i in 1..nums.len() {
+            for j in 0..i {
+                if nums[i] > nums[j] {
+                    dp[i] = max(dp[i], dp[j] + 1);
+                }
+            }
+        }
+
+        *dp.iter().max().unwrap()
+    }
+}