You are given an integer array nums.
Start by selecting a starting position curr such that nums[curr] == 0, and choose a movement direction of either left or right.
After that, you repeat the following process:
\n\ncurr is out of the range [0, n - 1], this process ends.nums[curr] == 0, move in the current direction by incrementing curr if you are moving right, or decrementing curr if you are moving left.nums[curr] > 0:\n\tnums[curr] by 1.A selection of the initial position curr and movement direction is considered valid if every element in nums becomes 0 by the end of the process.
Return the number of possible valid selections.
\n\n\n
Example 1:
\n\nInput: nums = [1,0,2,0,3]
\n\nOutput: 2
\n\nExplanation:
\n\nThe only possible valid selections are the following:
\n\ncurr = 3, and a movement direction to the left.\n\n\t[1,0,2,0,3] -> [1,0,2,0,3] -> [1,0,1,0,3] -> [1,0,1,0,3] -> [1,0,1,0,2] -> [1,0,1,0,2] -> [1,0,0,0,2] -> [1,0,0,0,2] -> [1,0,0,0,1] -> [1,0,0,0,1] -> [1,0,0,0,1] -> [1,0,0,0,1] -> [0,0,0,0,1] -> [0,0,0,0,1] -> [0,0,0,0,1] -> [0,0,0,0,1] -> [0,0,0,0,0].curr = 3, and a movement direction to the right.\n\t[1,0,2,0,3] -> [1,0,2,0,3] -> [1,0,2,0,2] -> [1,0,2,0,2] -> [1,0,1,0,2] -> [1,0,1,0,2] -> [1,0,1,0,1] -> [1,0,1,0,1] -> [1,0,0,0,1] -> [1,0,0,0,1] -> [1,0,0,0,0] -> [1,0,0,0,0] -> [1,0,0,0,0] -> [1,0,0,0,0] -> [0,0,0,0,0].Example 2:
\n\nInput: nums = [2,3,4,0,4,1,0]
\n\nOutput: 0
\n\nExplanation:
\n\nThere are no possible valid selections.
\n\n
Constraints:
\n\n1 <= nums.length <= 1000 <= nums[i] <= 100i where nums[i] == 0.Compiled with clang 19 using the latest C++ 23 standard, and libstdc++ provided by GCC 14.
Your code is compiled with level two optimization (-O2). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.
Most standard library headers are already included automatically for your convenience.
\"], \"java\": [\"Java\", \"OpenJDK 21. Using compile arguments: --enable-preview --release 21
Most standard library headers are already included automatically for your convenience.
\\r\\nIncludes Pair class from https://docs.oracle.com/javase/8/javafx/api/javafx/util/Pair.html.
Python 2.7.18.
Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.
\\r\\n\\r\\nFor Map/TreeMap data structure, you may use sortedcontainers library.
\\r\\n\\r\\nNote that Python 2.7 is not maintained anymore. For the latest Python, please choose Python3 instead.
\"], \"c\": [\"C\", \"Compiled with gcc 14 using the gnu11 standard.
Your code is compiled with level one optimization (-O2). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.
Most standard library headers are already included automatically for your convenience.
\\r\\n\\r\\nFor hash table operations, you may use uthash. \\\"uthash.h\\\" is included by default. Below are some examples:
\\r\\n\\r\\n1. Adding an item to a hash.\\r\\n
\\r\\nstruct hash_entry {\\r\\n int id; /* we'll use this field as the key */\\r\\n char name[10];\\r\\n UT_hash_handle hh; /* makes this structure hashable */\\r\\n};\\r\\n\\r\\nstruct hash_entry *users = NULL;\\r\\n\\r\\nvoid add_user(struct hash_entry *s) {\\r\\n HASH_ADD_INT(users, id, s);\\r\\n}\\r\\n\\r\\n\\r\\n\\r\\n2. Looking up an item in a hash:\\r\\n
\\r\\nstruct hash_entry *find_user(int user_id) {\\r\\n struct hash_entry *s;\\r\\n HASH_FIND_INT(users, &user_id, s);\\r\\n return s;\\r\\n}\\r\\n\\r\\n\\r\\n\\r\\n3. Deleting an item in a hash:\\r\\n
\\r\\nvoid delete_user(struct hash_entry *user) {\\r\\n HASH_DEL(users, user); \\r\\n}\\r\\n\\r\\n\"], \"csharp\": [\"C#\", \"C# 12 with .NET 8 runtime
\"], \"javascript\": [\"JavaScript\", \"Node.js 20.10.0.
Your code is run with --harmony flag, enabling new ES6 features.
lodash.js library is included by default.
\\r\\n\\r\\nFor Priority Queue / Queue data structures, you may use 5.4.0 version of datastructures-js/priority-queue and 4.2.3 version of datastructures-js/queue and 1.0.4 version of datastructures-js/deque.
\"], \"ruby\": [\"Ruby\", \"Ruby 3.2
Some common data structure implementations are provided in the Algorithms module: https://www.rubydoc.info/github/kanwei/algorithms/Algorithms
\"], \"swift\": [\"Swift\", \"Swift 5.10.
You may use swift-algorithms 1.2.0 and swift-collections 1.1.4.
\"], \"golang\": [\"Go\", \"Go 1.23
Support https://pkg.go.dev/github.com/emirpasic/gods@v1.18.1 and https://pkg.go.dev/github.com/emirpasic/gods/v2@v2.0.0-alpha library.
\"], \"python3\": [\"Python3\", \"Python 3.11.
Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.
\\r\\n\\r\\nFor Map/TreeMap data structure, you may use sortedcontainers library.
\"], \"scala\": [\"Scala\", \"Scala 3.3.1.
Kotlin 1.9.0.
We are using an experimental compiler provided by JetBrains.
\"], \"rust\": [\"Rust\", \"Rust 1.79.0. Your code will be compiled with opt-level 2.
Supports rand v0.8 and regex\\u00a0v1 from crates.io
\"], \"php\": [\"PHP\", \"PHP 8.2.
With bcmath module
\"], \"typescript\": [\"Typescript\", \"TypeScript 5.1.6, Node.js 20.10.0.
Compile Options: --alwaysStrict --strictBindCallApply --strictFunctionTypes --target ES2022
Your code is run with --harmony flag, enabling new ES2022 features.
lodash.js library is included by default.
\\r\\n\\r\\nFor Priority Queue / Queue data structures, you may use 5.4.0 version of datastructures-js/priority-queue and 4.2.3 version of datastructures-js/queue and 1.0.4 version of datastructures-js/deque.
\"], \"racket\": [\"Racket\", \"Racket CS v8.15
\\r\\n\\r\\nUsing #lang racket
Required data/gvector data/queue data/order data/heap automatically for your convenience
Dart 3.2. You may use package collection
\\r\\n\\r\\nYour code will be run directly without compiling
\"]}", "libraryUrl": null, "adminUrl": null, "challengeQuestion": null, "__typename": "QuestionNode" } } }