Done with DP-1

problem-1.py

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+# LEETCODE PROBLEM 322 COIN CHANGE
+# TIME COMPLEXITY:O(N*M) where N is the number of coins and M is the amount
+# SPACE COMPLEXITY: O(M) 
+# Any problem you faced while coding this: None
+
+
+class Solution(object):
+    def coinChange(self, coins, amount):
+        """
+        :type coins: List[int]
+        :type amount: int
+        :rtype: int
+        """
+        #Approach 1
+        # n=len(coins)+1
+        # m=amount+1
+        # matrix=[[0]*m for _ in range(n)]
+        # #(matrix)
+        # for i in range(1,m):
+        #     matrix[0][i]=float('inf')
+
+        # for i in range(1,n):
+        #     for j in range(1,m):
+        #         if (j>=coins[i-1]):
+        #             #matrix[i][j]=min(matrix[i-1][j-coins[i-1]]+1,matrix[i-1][j])
+        #             matrix[i][j] = min(matrix[i][j-coins[i-1]] + 1, matrix[i-1][j])
+        #         else:
+        #             matrix[i][j]=matrix[i-1][j]
+        # ans=matrix[n-1][m-1]
+        # return ans if ans !=float('inf') else -1
+
+        #Approach 2
+
+        m=amount+1
+        matrix=[float('inf')]*m
+        matrix[0]=0
+        for i in coins:
+            for j in range(i,m):
+                matrix[j]=min(matrix[j],matrix[j-i]+1)
+        return -1 if matrix[m-1]==float('inf') else matrix[m-1]

problem-2.py

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+# LEETCODE PROBLEM 198. HOUSE ROBBER
+# TIME COMPLEXITY: O(N) where N denotes the number of elements in an array
+# SPACE COMPLEXITY: O(1) 
+# Any problem you faced while coding this: None
+
+
+class Solution(object):
+    def rob(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        n = len(nums)
+        if n == 1:
+            return nums[0]
+
+        prev = nums[0]
+        current= max(nums[0], nums[1])
+        for i in range(2,len(nums)):
+            temp=current
+            current=max(temp,prev+nums[i])
+            prev=temp
+        return current