You are given a 0-indexed array of integers nums of length n, and a positive odd integer k.
The strength of x subarrays is defined as strength = sum[1] * x - sum[2] * (x - 1) + sum[3] * (x - 2) - sum[4] * (x - 3) + ... + sum[x] * 1 where sum[i] is the sum of the elements in the ith subarray. Formally, strength is sum of (-1)i+1 * sum[i] * (x - i + 1) over all i's such that 1 <= i <= x.
You need to select k disjoint subarrays from nums, such that their strength is maximum.
Return the maximum possible strength that can be obtained.
\n\nNote that the selected subarrays don't need to cover the entire array.
\n\n\n
Example 1:
\n\n\nInput: nums = [1,2,3,-1,2], k = 3\nOutput: 22\nExplanation: The best possible way to select 3 subarrays is: nums[0..2], nums[3..3], and nums[4..4]. The strength is (1 + 2 + 3) * 3 - (-1) * 2 + 2 * 1 = 22.\n\n\n
Example 2:
\n\n\nInput: nums = [12,-2,-2,-2,-2], k = 5\nOutput: 64\nExplanation: The only possible way to select 5 disjoint subarrays is: nums[0..0], nums[1..1], nums[2..2], nums[3..3], and nums[4..4]. The strength is 12 * 5 - (-2) * 4 + (-2) * 3 - (-2) * 2 + (-2) * 1 = 64.\n\n\n
Example 3:
\n\n\nInput: nums = [-1,-2,-3], k = 1\nOutput: -1\nExplanation: The best possible way to select 1 subarray is: nums[0..0]. The strength is -1.\n\n\n
\n
Constraints:
\n\n1 <= n <= 104-109 <= nums[i] <= 1091 <= k <= n1 <= n * k <= 106k is odd.dp[i][j][x == 0/1] be the maximum strength to select j disjoint subarrays from the original array’s suffix (nums[i..(n - 1)]), x denotes whether we select the element or not.",
"Initially dp[n][0][0] == 0.",
"We have \r\ndp[i][j][1] = nums[i] * get(j) + max(dp[i + 1][j - 1][0], dp[i + 1][j][1]) where get(j) = j if j is odd, otherwise -j.",
"We can select nums[i] as a separate subarray or select at least nums[i] and nums[i + 1] as the first subarray.\r\ndp[i][j][0] = max(dp[i + 1][j][0], dp[i][j][1]).",
"The answer is dp[0][k][0]."
],
"solution": null,
"status": null,
"sampleTestCase": "[1,2,3,-1,2]\n3",
"metaData": "{\n \"name\": \"maximumStrength\",\n \"params\": [\n {\n \"name\": \"nums\",\n \"type\": \"integer[]\"\n },\n {\n \"type\": \"integer\",\n \"name\": \"k\"\n }\n ],\n \"return\": {\n \"type\": \"long\"\n }\n}",
"judgerAvailable": true,
"judgeType": "large",
"mysqlSchemas": [],
"enableRunCode": true,
"enableTestMode": false,
"enableDebugger": true,
"envInfo": "{\"cpp\": [\"C++\", \"Compiled with clang 17 using the latest C++ 20 standard, and libstdc++ provided by GCC 11.
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 2.7.12.
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 will not be maintained past 2020. For the latest Python, please choose Python3 instead.
\"], \"c\": [\"C\", \"Compiled with gcc 11 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.
\"], \"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 5.9.
You may use swift-algorithms 1.2.0 and swift-collections 1.0.6.
\"], \"golang\": [\"Go\", \"Go 1.21
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 1.74.1
Supports rand v0.6\\u00a0from 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.
\"], \"racket\": [\"Racket\", \"Racket CS v8.11
\\r\\n\\r\\nUsing #lang racket
Required data/gvector data/queue data/order data/heap automatically for your convenience
Dart 3.2
\\r\\n\\r\\nYour code will be run directly without compiling
\"]}", "libraryUrl": null, "adminUrl": null, "challengeQuestion": null, "__typename": "QuestionNode" } } }