Create LongestIncreasingSubsequence.cpp

Dynamic Programming/Longest Increasing Subsequence/LongestIncreasingSubsequence.cpp

@@ -0,0 +1,40 @@
+// Memoization
+
+class Solution {
+public:
+
+ int solve(vector<int> &nums, vector<vector<int>> &dp, int n, int ind, int prev){
+ if(ind == n) return 0;
+ if(dp[ind][prev+1] != -1) return dp[ind][prev+1];
+ int notTake = solve(nums, dp, n, ind+1, prev);
+ int take = 0;
+ if(prev == -1 || nums[ind] > nums[prev])
+ take = 1 + solve(nums, dp, n, ind+1, ind);
+ return dp[ind][prev + 1] = max(take, notTake);
+ }
+
+ int lengthOfLIS(vector<int>& nums) {
+ int n = nums.size();
+ vector<vector<int>> dp(n, vector<int>(n+1, -1));
+ return solve(nums, dp, n, 0, -1);
+ }
+};
+
+
+// Tabulation - 1D
+
+class Solution {
+public:
+ int lengthOfLIS(vector<int>& nums) {
+ int n = nums.size(), maxi = INT_MIN;
+ vector<int> dp(n, 1);
+ for(int i = 0; i < n; i++){
+ for(int j = 0; j < i; j++){
+ if(nums[i] > nums[j] && dp[i] < 1 + dp[j])
+ dp[i] = 1 + dp[j];
+ }
+ maxi = max(maxi, dp[i]);
+ }
+ return maxi;
+ }
+};