Completed DP-3 Assignment

Delete_and_earn.java

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+// Time Complexity : O(n)
+// Space Complexity : O(n)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : No
+class Solution {
+    public int deleteAndEarn(int[] nums) {
+        int max=0;
+        for(int num: nums){
+            max = Math.max(max, num);
+        }
+        int[] arr= new int[max+1];
+        for(int num:nums){
+            arr[num]+=num;
+        }
+        int[] dp = new int[arr.length+1];
+        dp[0]=0;
+        dp[1] = Math.max(arr[0], arr[1]);
+        for(int i=2;i<=max;i++){
+            dp[i] = Math.max(dp[i-1],arr[i]+dp[i-2]);
+        }
+        return dp[max];
+    }
+}

Minimum_Falling_Path_Sum.java

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+// Time Complexity :O(N^2)
+// Space Complexity :O(N^2)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : Yes I am facing issue in implementing DP for this question. 
+class Solution {
+    Integer [][] memo;
+    public int minFallingPathSum(int[][] matrix) {
+        if(matrix==null || matrix.length==0) return 0;
+        int min = Integer.MAX_VALUE;
+        int n = matrix.length;
+        this.memo= new Integer[n][n];
+        for(int j=0;j<n;j++){
+            min=Math.min(min,helper(matrix,0,j));
+        }
+        return min;
+    }
+    private int helper(int[][] matrix, int i, int j){
+        int n = matrix.length;
+        // base 
+        if(j<0 || j>=n) return Integer.MAX_VALUE -10;
+        if (i==n) return 0;
+        if(memo[i][j]!= null) return memo[i][j];
+        // logic 
+        int down= helper(matrix,i+1,j);
+        int left = helper(matrix,i+1,j-1);
+        int right = helper(matrix,i+1,j+1); 
+        memo[i][j] = matrix[i][j] + Math.min(down,Math.min(left,right));
+        return memo[i][j];
+    }
+}