Latest problem solutions

Author: Garvit244

1000-1100q/1041.py

@@ -0,0 +1,61 @@
+'''
+On an infinite plane, a robot initially stands at (0, 0) and faces north.  The robot can receive one of three instructions:
+
+"G": go straight 1 unit;
+"L": turn 90 degrees to the left;
+"R": turn 90 degress to the right.
+The robot performs the instructions given in order, and repeats them forever.
+
+Return true if and only if there exists a circle in the plane such that the robot never leaves the circle.
+
+ 
+
+Example 1:
+
+Input: "GGLLGG"
+Output: true
+Explanation: 
+The robot moves from (0,0) to (0,2), turns 180 degrees, and then returns to (0,0).
+When repeating these instructions, the robot remains in the circle of radius 2 centered at the origin.
+Example 2:
+
+Input: "GG"
+Output: false
+Explanation: 
+The robot moves north indefinetely.
+Example 3:
+
+Input: "GL"
+Output: true
+Explanation: 
+The robot moves from (0, 0) -> (0, 1) -> (-1, 1) -> (-1, 0) -> (0, 0) -> ...
+ 
+
+Note:
+
+1 <= instructions.length <= 100
+instructions[i] is in {'G', 'L', 'R'}
+'''
+
+class Solution(object):
+    def isRobotBounded(self, instructions):
+        """
+        :type instructions: str
+        :rtype: bool
+        """
+        start_x, start_y = 0, 0
+        left, direct = 0, 0
+        moves = [[0, 1], [-1, 0], [0, -1], [1, 0]]
+        instructions = instructions*4
+        for instruction in instructions:
+            if instruction == 'G':
+                start_x += moves[direct][0]
+                start_y += moves[direct][1]
+            elif instruction == 'L':
+                direct = (direct+1)%4
+            elif instruction == 'R':
+                direct = (direct+3)%4
+                
+        if(start_x == 0 and start_y == 0):
+            return True
+        return False

1000-1100q/1042.py

@@ -0,0 +1,75 @@
+'''
+You have N gardens, labelled 1 to N.  In each garden, you want to plant one of 4 types of flowers.
+
+paths[i] = [x, y] describes the existence of a bidirectional path from garden x to garden y.
+
+Also, there is no garden that has more than 3 paths coming into or leaving it.
+
+Your task is to choose a flower type for each garden such that, for any two gardens connected by a path, they have different types of flowers.
+
+Return any such a choice as an array answer, where answer[i] is the type of flower planted in the (i+1)-th garden.  The flower types are denoted 1, 2, 3, or 4.  It is guaranteed an answer exists.
+
+ 
+
+Example 1:
+
+Input: N = 3, paths = [[1,2],[2,3],[3,1]]
+Output: [1,2,3]
+Example 2:
+
+Input: N = 4, paths = [[1,2],[3,4]]
+Output: [1,2,1,2]
+Example 3:
+
+Input: N = 4, paths = [[1,2],[2,3],[3,4],[4,1],[1,3],[2,4]]
+Output: [1,2,3,4]
+ 
+
+Note:
+
+1 <= N <= 10000
+0 <= paths.size <= 20000
+No garden has 4 or more paths coming into or leaving it.
+It is guaranteed an answer exists.
+'''
+
+class Solution(object):
+    def gardenNoAdj(self, N, paths):
+        """
+        :type N: int
+        :type paths: List[List[int]]
+        :rtype: List[int]
+        """            
+        plant = [1, 2, 3, 4]
+        result = [0 for _ in range(N)]
+        if not paths:
+            return [plant[index%4] for index in range(N)]
+        # print result
+        change = {}
+        update = []
+        for path in paths:
+            x, y = path[0]-1, path[1]-1
+                
+            if x in change:
+                change[x].append(y)
+            else:
+                change[x] = [y]
+                
+            if y in change:
+                change[y].append(x)
+            else:
+                change[y] = [x]
+        
+        for garden in range(N):
+            color_used = []
+            if garden in change:
+                subgarden = change[garden]
+                for subgarden in change[garden]:
+                    if result[subgarden]:
+                        color_used.append(result[subgarden])
+            color_rem = list(set([1, 2, 3, 4]) - set(color_used))
+            for color in color_rem:
+                result[garden] = color
+                break
+        return result
+ 

1000-1100q/1043.py

@@ -0,0 +1,43 @@
+'''
+Given an integer array A, you partition the array into (contiguous) subarrays of length at most K.  After partitioning, each subarray has their values changed to become the maximum value of that subarray.
+
+Return the largest sum of the given array after partitioning.
+
+ 
+
+Example 1:
+
+Input: A = [1,15,7,9,2,5,10], K = 3
+Output: 84
+Explanation: A becomes [15,15,15,9,10,10,10]
+ 
+
+Note:
+
+1 <= K <= A.length <= 500
+0 <= A[i] <= 10^6
+'''
+
+class Solution(object):
+    def maxSumAfterPartitioning(self, A, K):
+        """
+        :type A: List[int]
+        :type K: int
+        :rtype: int
+        """
+        if not A:
+            return 0
+        
+        N = len(A)
+        dp = [0]*(N+1)
+        for index_i in range(N):
+            maxi = 0
+            for index_j in range(index_i, index_i-K, -1):
+                if index_j >= 0 and index_j < len(A):
+                    maxi = max(maxi, A[index_j])
+                    
+                    dp[index_i+1] = max(dp[index_i+1], maxi*(index_i-index_j+1)+dp[index_j])
+            # print index_i, maxi
+            # print dp
+                    
+        return dp[-1]

README.md

@@ -14,6 +14,9 @@ Python solution of problems from [LeetCode](https://leetcode.com/).
 | # | Title | Solution | Difficulty |
 |---| ----- | -------- | ---------- |
 |1044|[Longest Duplicate Substring](https://leetcode.com/problems/longest-duplicate-substring)|[Python](./1000-1100q/1044.py)|Hard|
+|1043|[Partition Array for Maximum Sum](https://leetcode.com/problems/partition-array-for-maximum-sum/)|[Python](./1000-1100q/1043.py)|Medium|
+|1042|[Flower Planting With No Adjacent](https://leetcode.com/problems/flower-planting-with-no-adjacent)|[Python](./1000-1100q/1042.py)|Easy|
+|1041|[Robot Bounded In Circle](https://leetcode.com/problems/robot-bounded-in-circle)|[Python](./1000-1100q/1041.py)|Easy|
 |1039|[Minimum Score Triangulation of Polygon](https://leetcode.com/problems/minimum-score-triangulation-of-polygon)|[Python](./1000-1100q/1039.py)|Medium|
 |1038|[Binary Search Tree to Greater Sum Tree](https://leetcode.com/problems/binary-search-tree-to-greater-sum-tree/)|[Python](./1000-1100q/1038.py)|Medium|
 |1037|[Valid Boomerang](https://leetcode.com/problems/valid-boomerang/)|[Python](./1000-1100q/1037.py)|Easy|