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Suppose we have a matrix A of integers with R rows and C columns, we have to find the maximum score of a path starting from [0, 0] and ending at [R-1, C-1]. Here the scoring technique will be the minimum value in that path. For example, the value of the path 8 → 4 → 5 → 9 is 4. A path moves some number of times from one visited cell to any neighboring unvisited cell in one of the 4 cardinal directions (north, east, west, south).For example, if the grid is like −545126746The orange cells will be the ... Read More
There will never be redundant combinations in a Python dictionary because it is a hashmap. This means that each key will have exactly one associated value with it. This value can be a list or another dict though. So if you try to add a duplicate key likeExamplea = {'foo': 42, 'bar': 55} a['foo'] = 100 print(a)OutputThis will give the output{'foo': 100, 'bar': 55}If you really want multiple values for a single key, then you should probably use a list to be associated with the key and add values to that list.
Suppose we have a text, we have to find the lexicographically smallest subsequence of text that contains all the distinct characters of text exactly once. So if the input is like “cdadabcc”, then the output will be “adbc”.To solve this, we will follow these steps −Define a stack st, two maps last_o and considered, they are initially blankfor i in range length of text – 1 down to 0if text[i] is not present in last_o −last_o[text[i]] := iconsidered[text[i]] := falsei := 0while i < length of textif stack has no elementspush text[i] into stackconsidered[text[i]] := trueincrease i by 1otherwise stack ... Read More
You can use a list comprehension to truncate keys in a python dict. Iterate over the keys in the dict, and create a new dict with the truncated keys. exampledef truncate_keys(a, length): return dict((k[:length], v) for k, v in a.items()) a = {'foo': 125, 'bar': 'hello'} b = truncate_keys(a, 2) print(b)OutputThis will give the output{'fo': 125, 'ba': 'hello'}You need to vary about the name collision though. This is because if 2 strings have the same prefix, they will override the values.
Suppose we have a binary tree. A node is known as insufficient if every such root to leaf path intersecting this node has sum strictly less than limit. We have to delete all insufficient nodes simultaneously, and return the root of the resulting binary tree. So if the tree is like, and the limit is 1 −Then the output tree will be −To solve this, we will follow these steps −Define a method solve(), this will take root and limitif node has no left and right subtree, thenif value of root is less than 1, return null, otherwise rootif root ... Read More
You can get all the values using a call to dict.values(). Then you can call ", ".join on the values to concatenate just the values in the dict separated by commas. examplea = {'foo': "Hello", 'bar': "World"} vals = a.values() concat = ", ".join(vals) print(concat)OutputThis will give the output −Hello, World
The easiest way to convert a spreadsheet to Python dictionary is to use an external library like pandas. This provides very helpful features like to_dict on excel objects. You can use these like −Examplefrom pandas import * xls = ExcelFile('my_file.xls') data = xls.parse(xls.sheet_names[0]) print(data.to_dict())OutputThis will give the output −{'id': 10, 'name': "John"}
The JSON module is a very reliable library to serialize a Python dictionary into a string, and then back to a dictionary. The dumps function converts the dict to a string. exampleimport json my_dict = { 'foo': 42, 'bar': { 'baz': "Hello", 'poo': 124.2 } } my_json = json.dumps(my_dict) print(my_json)OutputThis will give the output −'{"foo": 42, "bar": {"baz": "Hello", "poo": 124.2}}'The loads function converts the string back to a dict. exampleimport json my_str = '{"foo": 42, "bar": {"baz": "Hello", "poo": 124.2}}' my_dict = json.loads(my_str) print(my_dict['bar']['baz'])OutputThis will give the output −Hello
Tuples are compared position by position: the first item of the first tuple is compared to the first item of the second tuple; if they are not equal, this is the result of the comparison, else the second item is considered, then the third and so on. example>>> a = (1, 2, 3) >>> b = (1, 2, 5) >>> a < b TrueThere is another type of comparison that takes into account similar and different elements. This can be performed using sets. Sets will take the tuples and take only unique values. Then you can perform a & operation that ... Read More
If you have a tuple of strings and you want to search for a particular string, You can use the in operator. exampletpl = ("Hello", "world", "Foo", "bar") print("world" in tpl)OutputThis will give the output −TrueExampleIf you want to check if there is a substring present. You can loop over the tuple and find it using:tpl = ("Hello", "world", "Foo", "bar") for i in tpl: if "orld" in i: print("Found orld in " + i )OutputThis will give the output −Found orld in world