knapsack.py

-Original file line number
+Diff line change
@@ -0,0 +1,28 @@
+    """
+    time - o(n)
+    space - o(n)
+    we create a 2d array where inner array size = capacity and number of arrays is equal to the number of weights
+    we iterate each array which represents a weight in the weights array and each inner array cell is the current capacity of the sack
+    if the current capacity is lesser than the weight we take the previous weight's value at the same capacity, if not we take max between
+    previous weight's value at that capacity and capacity - weight's value plus current capacity's value
+    (what value we'll currently have if we choose the weight along with the previous choice)
+    """
+    def knapsack(weights, values, capacity):
+        n = len(weights)
+        dp = [[0 for _ in range(capacity + 1)] for _ in range(n + 1)]
+        for i in range(1, n + 1):
+            for w in range(capacity + 1):
+                if weights[i - 1] <= w:
+                    # Include or exclude current item
+                    dp[i][w] = max(
+                        dp[i - 1][w],  # don't choose
+                        dp[i - 1][w - weights[i - 1]] + values[i - 1],  # choose
+                    )
+                else:
+                    # Cannot include current item
+                    dp[i][w] = dp[i - 1][w]
+        return dp[n][capacity]

two_sum.py

-Original file line number
+Diff line change
@@ -0,0 +1,18 @@
+    """
+    space = o(n)
+    time = o(n)
+    store numbers in a dictionary and if we have it's complement as seen before
+    we return the two nunmbers
+    """
+    from typing import List
+    class Solution:
+        def twoSum(self, nums: List[int], target: int) -> List[int]:
+            seen = {}
+            for i in range(len(nums)):
+                complement = target - nums[i]
+                if complement in seen:
+                    return [i, seen[complement]]
+                seen[nums[i]] = i

Competitive-Coding-2 #1159

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open

praxpk wants to merge 1 commit into super30admin:master from praxpk:master

-Original file line number
+Diff line change
@@ -0,0 +1,28 @@
+    """
+    time - o(n)
+    space - o(n)
+    we create a 2d array where inner array size = capacity and number of arrays is equal to the number of weights
+    we iterate each array which represents a weight in the weights array and each inner array cell is the current capacity of the sack
+    if the current capacity is lesser than the weight we take the previous weight's value at the same capacity, if not we take max between
+    previous weight's value at that capacity and capacity - weight's value plus current capacity's value
+    (what value we'll currently have if we choose the weight along with the previous choice)
+    """
+    def knapsack(weights, values, capacity):
+        n = len(weights)
+        dp = [[0 for _ in range(capacity + 1)] for _ in range(n + 1)]
+        for i in range(1, n + 1):
+            for w in range(capacity + 1):
+                if weights[i - 1] <= w:
+                    # Include or exclude current item
+                    dp[i][w] = max(
+                        dp[i - 1][w],  # don't choose
+                        dp[i - 1][w - weights[i - 1]] + values[i - 1],  # choose
+                    )
+                else:
+                    # Cannot include current item
+                    dp[i][w] = dp[i - 1][w]
+        return dp[n][capacity]

-Original file line number
+Diff line change
@@ -0,0 +1,18 @@
+    """
+    space = o(n)
+    time = o(n)
+    store numbers in a dictionary and if we have it's complement as seen before
+    we return the two nunmbers
+    """
+    from typing import List
+    class Solution:
+        def twoSum(self, nums: List[int], target: int) -> List[int]:
+            seen = {}
+            for i in range(len(nums)):
+                complement = target - nums[i]
+                if complement in seen:
+                    return [i, seen[complement]]
+                seen[nums[i]] = i

Provide feedback