|
59 | 59 |
|
60 | 60 | <!-- 这里可写通用的实现逻辑 -->
|
61 | 61 |
|
| 62 | +**方法一:树状数组** |
| 63 | + |
| 64 | +本题属于二维偏序问题。 |
| 65 | + |
| 66 | +二维偏序是这样一类问题:给定若干个点对 $(a_1, b_1)$, $(a_2, b_2)$, $\cdots$, $(a_n, b_n)$,并定义某种偏序关系,现在给定点 $(a_i, b_i)$,求满足偏序关系的点对 $(a_j, b_j)$ 中的数量/最值。即: |
| 67 | + |
| 68 | +$$ |
| 69 | +\left(a_{j}, b_{j}\right) \prec\left(a_{i}, b_{i}\right) \stackrel{\text { def }}{=} a_{j} \lesseqgtr a_{i} \text { and } b_{j} \lesseqgtr b_{i} |
| 70 | +$$ |
| 71 | + |
| 72 | +二维偏序的一般解决方法是排序一维,用数据结构处理第二维(这种数据结构一般是树状数组)。 |
| 73 | + |
| 74 | +对于本题,我们可以创建一个数组 $nums$,其中 $nums[i]=(nums_1[i], nums_2[i])$,然后对 $nums$ 按照 $nums_1$ 从大到小的顺序排序,将查询 $queries$ 也按照 $x$ 从大到小的顺序排序。 |
| 75 | + |
| 76 | +接下来,遍历每个查询 $queries[i] = (x, y)$,对于当前查询,我们循环将 $nums$ 中所有大于等于 $x$ 的元素的 $nums_2$ 的值插入到树状数组中,树状数组维护的是离散化后的 $nums_2$ 的区间中 $nums_1 + nums_2$ 的最大值。那么我们只需要在树状数组中查询大于等于离散化后的 $y$ 区间对应的最大值即可。注意,由于树状数组维护的是前缀最大值,所以我们在实现上,可以将 $nums_2$ 反序插入到树状数组中。 |
| 77 | + |
| 78 | +时间复杂度 $O((n + m) \times \log n + m \times \log m)$,空间复杂度 $O(n + m)$。其中 $n$ 是数组 $nums$ 的长度,而 $m$ 是数组 $queries$ 的长度。 |
| 79 | + |
62 | 80 | <!-- tabs:start -->
|
63 | 81 |
|
64 | 82 | ### **Python3**
|
65 | 83 |
|
66 | 84 | <!-- 这里可写当前语言的特殊实现逻辑 -->
|
67 | 85 |
|
68 | 86 | ```python
|
69 |
| - |
| 87 | +class BinaryIndexedTree: |
| 88 | + __slots__ = ["n", "c"] |
| 89 | + |
| 90 | + def __init__(self, n: int): |
| 91 | + self.n = n |
| 92 | + self.c = [-1] * (n + 1) |
| 93 | + |
| 94 | + def update(self, x: int, v: int): |
| 95 | + while x <= self.n: |
| 96 | + self.c[x] = max(self.c[x], v) |
| 97 | + x += x & -x |
| 98 | + |
| 99 | + def query(self, x: int) -> int: |
| 100 | + mx = -1 |
| 101 | + while x: |
| 102 | + mx = max(mx, self.c[x]) |
| 103 | + x -= x & -x |
| 104 | + return mx |
| 105 | + |
| 106 | + |
| 107 | +class Solution: |
| 108 | + def maximumSumQueries( |
| 109 | + self, nums1: List[int], nums2: List[int], queries: List[List[int]] |
| 110 | + ) -> List[int]: |
| 111 | + nums = sorted(zip(nums1, nums2), key=lambda x: -x[0]) |
| 112 | + nums2.sort() |
| 113 | + n, m = len(nums1), len(queries) |
| 114 | + ans = [-1] * m |
| 115 | + j = 0 |
| 116 | + tree = BinaryIndexedTree(n) |
| 117 | + for i in sorted(range(m), key=lambda i: -queries[i][0]): |
| 118 | + x, y = queries[i] |
| 119 | + while j < n and nums[j][0] >= x: |
| 120 | + k = n - bisect_left(nums2, nums[j][1]) |
| 121 | + tree.update(k, nums[j][0] + nums[j][1]) |
| 122 | + j += 1 |
| 123 | + k = n - bisect_left(nums2, y) |
| 124 | + ans[i] = tree.query(k) |
| 125 | + return ans |
70 | 126 | ```
|
71 | 127 |
|
72 | 128 | ### **Java**
|
73 | 129 |
|
74 | 130 | <!-- 这里可写当前语言的特殊实现逻辑 -->
|
75 | 131 |
|
| 132 | +```java |
| 133 | +class BinaryIndexedTree { |
| 134 | + private int n; |
| 135 | + private int[] c; |
| 136 | + |
| 137 | + public BinaryIndexedTree(int n) { |
| 138 | + this.n = n; |
| 139 | + c = new int[n + 1]; |
| 140 | + Arrays.fill(c, -1); |
| 141 | + } |
| 142 | + |
| 143 | + public void update(int x, int v) { |
| 144 | + while (x <= n) { |
| 145 | + c[x] = Math.max(c[x], v); |
| 146 | + x += x & -x; |
| 147 | + } |
| 148 | + } |
| 149 | + |
| 150 | + public int query(int x) { |
| 151 | + int mx = -1; |
| 152 | + while (x > 0) { |
| 153 | + mx = Math.max(mx, c[x]); |
| 154 | + x -= x & -x; |
| 155 | + } |
| 156 | + return mx; |
| 157 | + } |
| 158 | +} |
| 159 | + |
| 160 | +class Solution { |
| 161 | + public int[] maximumSumQueries(int[] nums1, int[] nums2, int[][] queries) { |
| 162 | + int n = nums1.length; |
| 163 | + int[][] nums = new int[n][0]; |
| 164 | + for (int i = 0; i < n; ++i) { |
| 165 | + nums[i] = new int[] {nums1[i], nums2[i]}; |
| 166 | + } |
| 167 | + Arrays.sort(nums, (a, b) -> b[0] - a[0]); |
| 168 | + Arrays.sort(nums2); |
| 169 | + int m = queries.length; |
| 170 | + Integer[] idx = new Integer[m]; |
| 171 | + for (int i = 0; i < m; ++i) { |
| 172 | + idx[i] = i; |
| 173 | + } |
| 174 | + Arrays.sort(idx, (i, j) -> queries[j][0] - queries[i][0]); |
| 175 | + int[] ans = new int[m]; |
| 176 | + int j = 0; |
| 177 | + BinaryIndexedTree tree = new BinaryIndexedTree(n); |
| 178 | + for (int i : idx) { |
| 179 | + int x = queries[i][0], y = queries[i][1]; |
| 180 | + for (; j < n && nums[j][0] >= x; ++j) { |
| 181 | + int k = n - Arrays.binarySearch(nums2, nums[j][1]); |
| 182 | + tree.update(k, nums[j][0] + nums[j][1]); |
| 183 | + } |
| 184 | + int p = Arrays.binarySearch(nums2, y); |
| 185 | + int k = p >= 0 ? n - p : n + p + 1; |
| 186 | + ans[i] = tree.query(k); |
| 187 | + } |
| 188 | + return ans; |
| 189 | + } |
| 190 | +} |
| 191 | +``` |
| 192 | + |
76 | 193 | ```java
|
77 | 194 | class Solution {
|
78 | 195 | public int[] maximumSumQueries(int[] nums1, int[] nums2, int[][] q) {
|
@@ -121,13 +238,193 @@ class Solution {
|
121 | 238 | ### **C++**
|
122 | 239 |
|
123 | 240 | ```cpp
|
| 241 | +class BinaryIndexedTree { |
| 242 | +private: |
| 243 | + int n; |
| 244 | + vector<int> c; |
| 245 | + |
| 246 | +public: |
| 247 | + BinaryIndexedTree(int n) { |
| 248 | + this->n = n; |
| 249 | + c.resize(n + 1, -1); |
| 250 | + } |
| 251 | + |
| 252 | + void update(int x, int v) { |
| 253 | + while (x <= n) { |
| 254 | + c[x] = max(c[x], v); |
| 255 | + x += x & -x; |
| 256 | + } |
| 257 | + } |
124 | 258 |
|
| 259 | + int query(int x) { |
| 260 | + int mx = -1; |
| 261 | + while (x > 0) { |
| 262 | + mx = max(mx, c[x]); |
| 263 | + x -= x & -x; |
| 264 | + } |
| 265 | + return mx; |
| 266 | + } |
| 267 | +}; |
| 268 | + |
| 269 | +class Solution { |
| 270 | +public: |
| 271 | + vector<int> maximumSumQueries(vector<int>& nums1, vector<int>& nums2, vector<vector<int>>& queries) { |
| 272 | + vector<pair<int, int>> nums; |
| 273 | + int n = nums1.size(), m = queries.size(); |
| 274 | + for (int i = 0; i < n; ++i) { |
| 275 | + nums.emplace_back(-nums1[i], nums2[i]); |
| 276 | + } |
| 277 | + sort(nums.begin(), nums.end()); |
| 278 | + sort(nums2.begin(), nums2.end()); |
| 279 | + vector<int> idx(m); |
| 280 | + iota(idx.begin(), idx.end(), 0); |
| 281 | + sort(idx.begin(), idx.end(), [&](int i, int j) { return queries[j][0] < queries[i][0]; }); |
| 282 | + vector<int> ans(m); |
| 283 | + int j = 0; |
| 284 | + BinaryIndexedTree tree(n); |
| 285 | + for (int i : idx) { |
| 286 | + int x = queries[i][0], y = queries[i][1]; |
| 287 | + for (; j < n && -nums[j].first >= x; ++j) { |
| 288 | + int k = nums2.end() - lower_bound(nums2.begin(), nums2.end(), nums[j].second); |
| 289 | + tree.update(k, -nums[j].first + nums[j].second); |
| 290 | + } |
| 291 | + int k = nums2.end() - lower_bound(nums2.begin(), nums2.end(), y); |
| 292 | + ans[i] = tree.query(k); |
| 293 | + } |
| 294 | + return ans; |
| 295 | + } |
| 296 | +}; |
125 | 297 | ```
|
126 | 298 |
|
127 | 299 | ### **Go**
|
128 | 300 |
|
129 | 301 | ```go
|
| 302 | +type BinaryIndexedTree struct { |
| 303 | + n int |
| 304 | + c []int |
| 305 | +} |
| 306 | +
|
| 307 | +func NewBinaryIndexedTree(n int) BinaryIndexedTree { |
| 308 | + c := make([]int, n+1) |
| 309 | + for i := range c { |
| 310 | + c[i] = -1 |
| 311 | + } |
| 312 | + return BinaryIndexedTree{n: n, c: c} |
| 313 | +} |
| 314 | +
|
| 315 | +func (bit *BinaryIndexedTree) update(x, v int) { |
| 316 | + for x <= bit.n { |
| 317 | + bit.c[x] = max(bit.c[x], v) |
| 318 | + x += x & -x |
| 319 | + } |
| 320 | +} |
| 321 | +
|
| 322 | +func (bit *BinaryIndexedTree) query(x int) int { |
| 323 | + mx := -1 |
| 324 | + for x > 0 { |
| 325 | + mx = max(mx, bit.c[x]) |
| 326 | + x -= x & -x |
| 327 | + } |
| 328 | + return mx |
| 329 | +} |
| 330 | +
|
| 331 | +func maximumSumQueries(nums1 []int, nums2 []int, queries [][]int) []int { |
| 332 | + n, m := len(nums1), len(queries) |
| 333 | + nums := make([][2]int, n) |
| 334 | + for i := range nums { |
| 335 | + nums[i] = [2]int{nums1[i], nums2[i]} |
| 336 | + } |
| 337 | + sort.Slice(nums, func(i, j int) bool { return nums[j][0] < nums[i][0] }) |
| 338 | + sort.Ints(nums2) |
| 339 | + idx := make([]int, m) |
| 340 | + for i := range idx { |
| 341 | + idx[i] = i |
| 342 | + } |
| 343 | + sort.Slice(idx, func(i, j int) bool { return queries[idx[j]][0] < queries[idx[i]][0] }) |
| 344 | + tree := NewBinaryIndexedTree(n) |
| 345 | + ans := make([]int, m) |
| 346 | + j := 0 |
| 347 | + for _, i := range idx { |
| 348 | + x, y := queries[i][0], queries[i][1] |
| 349 | + for ; j < n && nums[j][0] >= x; j++ { |
| 350 | + k := n - sort.SearchInts(nums2, nums[j][1]) |
| 351 | + tree.update(k, nums[j][0]+nums[j][1]) |
| 352 | + } |
| 353 | + k := n - sort.SearchInts(nums2, y) |
| 354 | + ans[i] = tree.query(k) |
| 355 | + } |
| 356 | + return ans |
| 357 | +} |
| 358 | +``` |
| 359 | + |
| 360 | +### **TypeScript** |
130 | 361 |
|
| 362 | +```ts |
| 363 | +class BinaryIndexedTree { |
| 364 | + private n: number; |
| 365 | + private c: number[]; |
| 366 | + |
| 367 | + constructor(n: number) { |
| 368 | + this.n = n; |
| 369 | + this.c = Array(n + 1).fill(-1); |
| 370 | + } |
| 371 | + |
| 372 | + update(x: number, v: number): void { |
| 373 | + while (x <= this.n) { |
| 374 | + this.c[x] = Math.max(this.c[x], v); |
| 375 | + x += x & -x; |
| 376 | + } |
| 377 | + } |
| 378 | + |
| 379 | + query(x: number): number { |
| 380 | + let mx = -1; |
| 381 | + while (x > 0) { |
| 382 | + mx = Math.max(mx, this.c[x]); |
| 383 | + x -= x & -x; |
| 384 | + } |
| 385 | + return mx; |
| 386 | + } |
| 387 | +} |
| 388 | + |
| 389 | +function maximumSumQueries(nums1: number[], nums2: number[], queries: number[][]): number[] { |
| 390 | + const n = nums1.length; |
| 391 | + const m = queries.length; |
| 392 | + const nums: [number, number][] = []; |
| 393 | + for (let i = 0; i < n; ++i) { |
| 394 | + nums.push([nums1[i], nums2[i]]); |
| 395 | + } |
| 396 | + nums.sort((a, b) => b[0] - a[0]); |
| 397 | + nums2.sort((a, b) => a - b); |
| 398 | + const idx: number[] = Array(m) |
| 399 | + .fill(0) |
| 400 | + .map((_, i) => i); |
| 401 | + idx.sort((i, j) => queries[j][0] - queries[i][0]); |
| 402 | + const ans: number[] = Array(m).fill(0); |
| 403 | + let j = 0; |
| 404 | + const search = (x: number) => { |
| 405 | + let [l, r] = [0, n]; |
| 406 | + while (l < r) { |
| 407 | + const mid = (l + r) >> 1; |
| 408 | + if (nums2[mid] >= x) { |
| 409 | + r = mid; |
| 410 | + } else { |
| 411 | + l = mid + 1; |
| 412 | + } |
| 413 | + } |
| 414 | + return l; |
| 415 | + }; |
| 416 | + const tree = new BinaryIndexedTree(n); |
| 417 | + for (const i of idx) { |
| 418 | + const [x, y] = queries[i]; |
| 419 | + for (; j < n && nums[j][0] >= x; ++j) { |
| 420 | + const k = n - search(nums[j][1]); |
| 421 | + tree.update(k, nums[j][0] + nums[j][1]); |
| 422 | + } |
| 423 | + const k = n - search(y); |
| 424 | + ans[i] = tree.query(k); |
| 425 | + } |
| 426 | + return ans; |
| 427 | +} |
131 | 428 | ```
|
132 | 429 |
|
133 | 430 | ### **...**
|
|
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