結果
問題 | No.1332 Range Nearest Query |
ユーザー | 草苺奶昔 |
提出日時 | 2024-04-15 00:16:33 |
言語 | Go (1.22.1) |
結果 |
AC
|
実行時間 | 630 ms / 2,500 ms |
コード長 | 18,819 bytes |
コンパイル時間 | 10,059 ms |
コンパイル使用メモリ | 233,696 KB |
実行使用メモリ | 23,488 KB |
最終ジャッジ日時 | 2024-10-04 06:33:43 |
合計ジャッジ時間 | 33,740 ms |
ジャッジサーバーID (参考情報) |
judge3 / judge5 |
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テストケース
テストケース表示入力 | 結果 | 実行時間 実行使用メモリ |
---|---|---|
testcase_00 | AC | 1 ms
6,820 KB |
testcase_01 | AC | 1 ms
6,816 KB |
testcase_02 | AC | 1 ms
6,816 KB |
testcase_03 | AC | 600 ms
20,468 KB |
testcase_04 | AC | 603 ms
20,480 KB |
testcase_05 | AC | 595 ms
20,476 KB |
testcase_06 | AC | 504 ms
20,228 KB |
testcase_07 | AC | 506 ms
20,232 KB |
testcase_08 | AC | 507 ms
20,220 KB |
testcase_09 | AC | 501 ms
20,224 KB |
testcase_10 | AC | 504 ms
20,224 KB |
testcase_11 | AC | 515 ms
20,228 KB |
testcase_12 | AC | 515 ms
20,232 KB |
testcase_13 | AC | 502 ms
20,232 KB |
testcase_14 | AC | 502 ms
20,232 KB |
testcase_15 | AC | 508 ms
20,232 KB |
testcase_16 | AC | 629 ms
20,228 KB |
testcase_17 | AC | 624 ms
20,232 KB |
testcase_18 | AC | 630 ms
20,224 KB |
testcase_19 | AC | 624 ms
20,228 KB |
testcase_20 | AC | 628 ms
20,220 KB |
testcase_21 | AC | 623 ms
20,228 KB |
testcase_22 | AC | 625 ms
20,224 KB |
testcase_23 | AC | 624 ms
20,220 KB |
testcase_24 | AC | 622 ms
20,224 KB |
testcase_25 | AC | 619 ms
20,220 KB |
testcase_26 | AC | 431 ms
20,196 KB |
testcase_27 | AC | 398 ms
20,192 KB |
testcase_28 | AC | 106 ms
6,820 KB |
testcase_29 | AC | 118 ms
6,820 KB |
testcase_30 | AC | 119 ms
6,824 KB |
testcase_31 | AC | 113 ms
6,816 KB |
testcase_32 | AC | 123 ms
6,820 KB |
testcase_33 | AC | 123 ms
6,820 KB |
testcase_34 | AC | 119 ms
6,816 KB |
testcase_35 | AC | 116 ms
6,816 KB |
testcase_36 | AC | 114 ms
6,816 KB |
testcase_37 | AC | 120 ms
6,820 KB |
testcase_38 | AC | 469 ms
10,000 KB |
testcase_39 | AC | 319 ms
7,840 KB |
testcase_40 | AC | 606 ms
23,488 KB |
testcase_41 | AC | 366 ms
7,964 KB |
testcase_42 | AC | 458 ms
8,584 KB |
testcase_43 | AC | 401 ms
12,124 KB |
testcase_44 | AC | 570 ms
18,052 KB |
testcase_45 | AC | 529 ms
16,824 KB |
testcase_46 | AC | 433 ms
10,568 KB |
testcase_47 | AC | 492 ms
15,764 KB |
ソースコード
// 维护区间贡献的 Wavelet Matrix // !注意查询区间贡献时, 异或无效 // CountRange(start, end, a, b, xor) - 区间 [start, end) 中值在 [a, b) 之间的数的个数和这些数的和. // CountPrefix(start, end, x, xor) - 区间 [start, end) 中值在 [0, x) 之间的数的个数和这些数的和. // SumRange(start, end, k1, k2, xor) - 区间 [start, end) 中第 k1 到第 k2 小的数的和. // SumPrefix(start, end, k, xor) - 区间 [start, end) 中值小于等于 k 的数的和. // Kth(start, end, k, xor) - 区间 [start, end) 中第 k(k>=0) 小的数. // KthValueAndSum(start, end, k, xor) - 区间 [start, end) 中第 k 小的数(0-indexed) 和前 k 小的数的和(不包括这个数). // Median(start, end, upper, xor) - 区间 [start, end) 中的中位数. // SumAll(start, end) - 区间 [start, end) 中所有数的和. // Floor(start, end, x, xor) - 区间 [start, end) 中值小于等于 x 的最大值 // Ceil(start, end, x, xor) - 区间 [start, end) 中值大于等于 x 的最小值 // MaxRight(start, end, xor, check) - 返回使得 check(count,prefixSum) 为 true 的最大(count,prefixSum), 其中prefixSum为[0,val)内的数的和. package main import ( "bufio" "fmt" "math/bits" "os" "sort" ) func main() { // demo() // 区间最短距离和() // abc281_e() yuki1332() // yuki2065() } func demo() { nums := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10} wm := NewWaveletMatrixWithSum(nums, nums, -1, false) fmt.Println(wm.CountRange(0, 3, 3, 7, 0)) fmt.Println(wm.KthValueAndSum(1, 5, 0, 0)) nums = []int{1, 2, 3, 4, 5} wm = NewWaveletMatrixWithSum(nums, nums, -1, false) fmt.Println(wm.KthValueAndSum(0, 5, 2, 0)) fmt.Println(wm.KthValueAndSum(0, 6, 5, 0)) fmt.Println(wm.SumAll(0, 4)) fmt.Println(wm.Floor(0, 5, 4, 0)) fmt.Println(wm.Kth(0, 5, 1, 0)) } func abc281_e() { in := bufio.NewReader(os.Stdin) out := bufio.NewWriter(os.Stdout) defer out.Flush() var n, m, k int32 fmt.Fscan(in, &n, &m, &k) nums := make([]int, n) for i := range nums { fmt.Fscan(in, &nums[i]) } wm := NewWaveletMatrixWithSum(nums, nums, -1, false) for i := int32(0); i < n-m+1; i++ { _, res := wm.KthValueAndSum(i, i+m, k, 0) fmt.Fprintln(out, res) } } // 子数组所有数到中位数的距离和(区间中位数距离和) // https://yukicoder.me/problems/no/924 // n,q<=2e5 // -1e9 <= nums[i] <= 1e9 // 给定n个查询[l,r] // !求区间[l,r]中位数到区间[l,r]中每个数的距离之和 // !也就求函数 f(x)= ∑|nums[i]-x| (l<=i<=right) 的最小值 // !区间中位数 func 区间最短距离和() { in := bufio.NewReader(os.Stdin) out := bufio.NewWriter(os.Stdout) defer out.Flush() var n, q int fmt.Fscan(in, &n, &q) OFFSET := int(1e9 + 10) nums := make([]int, n) for i := range nums { fmt.Fscan(in, &nums[i]) nums[i] += OFFSET } preSum := make([]int, n+1) for i := 0; i < n; i++ { preSum[i+1] = preSum[i] + nums[i] } wm := NewWaveletMatrixWithSum(nums, nums, -1, false) for i := 0; i < q; i++ { var start, end int32 fmt.Fscan(in, &start, &end) start-- n := end - start lowerCount := n / 2 ceilCount := n - lowerCount mid, lowerSum := wm.KthValueAndSum(start, end, lowerCount, 0) allSum := preSum[end] - preSum[start] ceilSum := allSum - lowerSum res := 0 res += mid*int(lowerCount) - lowerSum res += ceilSum - mid*int(ceilCount) fmt.Fprintln(out, res) } } // No.1332 Range Nearest Query // https://yukicoder.me/problems/no/1332 // 区间最近值(无序数组区间前驱后继)查询 // !对每个查询[left,right,x],输出左闭右开区间内的数到给定数x的最小距离 // n<=3e5 q<=1e5 nums[i]<=1e9 func yuki1332() { in := bufio.NewReader(os.Stdin) out := bufio.NewWriter(os.Stdout) defer out.Flush() var n int fmt.Fscan(in, &n) nums := make([]int, n) for i := 0; i < n; i++ { fmt.Fscan(in, &nums[i]) } M := NewWaveletMatrixWithSum(nums, nil, -1, false) var q int fmt.Fscan(in, &q) for i := 0; i < q; i++ { var start, end int32 var x int fmt.Fscan(in, &start, &end, &x) start-- res := INF floor := M.Floor(start, end, x, 0) // 小于等于x的最大值 if floor != -INF { res = min(res, abs(floor-x)) } ceiling := M.Ceil(start, end, x, 0) // 大于等于x的最小值 if ceiling != INF { res = min(res, abs(ceiling-x)) } fmt.Fprintln(out, res) } } // No.2065 Sum of Min (区间chMin之和) // https://yukicoder.me/problems/no/2065 func yuki2065() { in := bufio.NewReader(os.Stdin) out := bufio.NewWriter(os.Stdout) defer out.Flush() var n int32 fmt.Fscan(in, &n) } const INF WmValue = 1e18 type WmValue = int type WmSum = int func (*WaveletMatrixWithSum) e() WmSum { return 0 } func (*WaveletMatrixWithSum) op(a, b WmSum) WmSum { return a + b } func (*WaveletMatrixWithSum) inv(a WmSum) WmSum { return -a } type WaveletMatrixWithSum struct { n, log int32 mid []int32 bv []*BitVector key []WmValue setLog bool presum [][]WmSum compress bool } // nums: 数组元素. // sumData: 和数据.nil表示不需要和数据. // log: 如果需要支持异或查询, 需要传入log.-1表示默认. // compress: 是否对nums进行离散化. func NewWaveletMatrixWithSum(nums []WmValue, sumData []WmSum, log int32, compress bool) *WaveletMatrixWithSum { wm := &WaveletMatrixWithSum{} wm.build(nums, sumData, log, compress) return wm } func (wm *WaveletMatrixWithSum) build(nums []WmValue, sumData []WmSum, log int32, compress bool) { numsCopy := append(nums[:0:0], nums...) sumDataCopy := append(sumData[:0:0], sumData...) wm.n = int32(len(numsCopy)) wm.log = log wm.compress = compress wm.setLog = log != -1 if wm.n == 0 { wm.log = 0 return } makeSum := len(sumData) > 0 if compress { if wm.setLog { panic("compress and log should not be set at the same time") } wm.key = make([]WmValue, 0, wm.n) order := wm.argSort(numsCopy) for _, i := range order { if len(wm.key) == 0 || wm.key[len(wm.key)-1] != numsCopy[i] { wm.key = append(wm.key, numsCopy[i]) } numsCopy[i] = WmValue(len(wm.key) - 1) } } if wm.log == -1 { tmp := wm.maxs(numsCopy) if tmp < 1 { tmp = 1 } wm.log = int32(bits.Len(uint(tmp))) } wm.mid = make([]int32, wm.log) wm.bv = make([]*BitVector, wm.log) for i := range wm.bv { wm.bv[i] = NewBitVector(wm.n) } if makeSum { wm.presum = make([][]WmSum, 1+wm.log) for i := range wm.presum { sums := make([]WmSum, wm.n+1) for j := range sums { sums[j] = wm.e() } wm.presum[i] = sums } } if len(sumDataCopy) == 0 { sumDataCopy = make([]WmSum, len(numsCopy)) } A, S := numsCopy, sumDataCopy A0, A1 := make([]WmValue, wm.n), make([]WmValue, wm.n) S0, S1 := make([]WmSum, wm.n), make([]WmSum, wm.n) for d := wm.log - 1; d >= -1; d-- { p0, p1 := int32(0), int32(0) if makeSum { tmp := wm.presum[d+1] for i := int32(0); i < wm.n; i++ { tmp[i+1] = wm.op(tmp[i], S[i]) } } if d == -1 { break } for i := int32(0); i < wm.n; i++ { f := (A[i] >> d & 1) == 1 if !f { if makeSum { S0[p0] = S[i] } A0[p0] = A[i] p0++ } else { if makeSum { S1[p1] = S[i] } wm.bv[d].Set(i) A1[p1] = A[i] p1++ } } wm.mid[d] = p0 wm.bv[d].Build() A, A0 = A0, A S, S0 = S0, S for i := int32(0); i < p1; i++ { A[p0+i] = A1[i] S[p0+i] = S1[i] } } } // 区间 [start, end) 中范围在 [a, b) 中的元素的个数. func (wm *WaveletMatrixWithSum) CountRange(start, end int32, a, b WmValue, xorVal WmValue) int32 { return wm.CountPrefix(start, end, b, xorVal) - wm.CountPrefix(start, end, a, xorVal) } func (wm *WaveletMatrixWithSum) SumRange(start, end, k1, k2 int32, xorVal WmValue) WmSum { if k1 >= k2 { return wm.e() } add := wm.SumPrefix(start, end, k2, xorVal) sub := wm.SumPrefix(start, end, k1, xorVal) return wm.op(add, wm.inv(sub)) } // 返回区间 [start, end) 中 范围在 [0, x) 中的元素的个数. func (wm *WaveletMatrixWithSum) CountPrefix(start, end int32, x WmValue, xor WmValue) int32 { if xor != 0 { if !wm.setLog { panic("log should be set when xor is used") } } if wm.compress { x = wm.lowerBound(wm.key, x) } if x == 0 { return 0 } if x >= 1<<wm.log { return end - start } count := int32(0) for d := wm.log - 1; d >= 0; d-- { add := (x>>d)&1 == 1 f := (xor>>d)&1 == 1 l0, r0 := wm.bv[d].Rank(start, false), wm.bv[d].Rank(end, false) kf := int32(0) if f { kf = (end - start - r0 + l0) } else { kf = (r0 - l0) } if add { count += kf if f { start, end = l0, r0 } else { start += wm.mid[d] - l0 end += wm.mid[d] - r0 } } else { if !f { start, end = l0, r0 } else { start += wm.mid[d] - l0 end += wm.mid[d] - r0 } } } return count } // 返回区间 [start, end) 中 [0, k) 的和. func (wm *WaveletMatrixWithSum) SumPrefix(start, end, k int32, xor WmValue) WmSum { _, sum := wm.KthValueAndSum(start, end, k, xor) return sum } // [start, end)区间内第k(k>=0)小的元素. func (wm *WaveletMatrixWithSum) Kth(start, end, k int32, xorVal WmValue) WmValue { if xorVal != 0 { if !wm.setLog { panic("log should be set") } } count := int32(0) res := WmValue(0) for d := wm.log - 1; d >= 0; d-- { f := (xorVal>>d)&1 == 1 l0, r0 := wm.bv[d].Rank(start, false), wm.bv[d].Rank(end, false) var c int32 if f { c = (end - start) - (r0 - l0) } else { c = r0 - l0 } if count+c > k { if !f { start, end = l0, r0 } else { start += wm.mid[d] - l0 end += wm.mid[d] - r0 } } else { count += c res |= 1 << d if !f { start += wm.mid[d] - l0 end += wm.mid[d] - r0 } else { start, end = l0, r0 } } } if wm.compress { res = wm.key[res] } return res } // 返回区间 [start, end) 中的 (第k小的元素, 前k个元素(不包括第k小的元素) 的 op 的结果). // 如果k >= end-start, 返回 (-1, 区间 op 的结果). func (wm *WaveletMatrixWithSum) KthValueAndSum(start, end, k int32, xorVal WmValue) (WmValue, WmSum) { if start >= end { return -1, wm.e() } if k >= end-start { return -1, wm.SumAll(start, end) } if xorVal != 0 { if !wm.setLog { panic("log should be set when xor is used") } } if len(wm.presum) == 0 { panic("sumData is not provided") } count := int32(0) sum := wm.e() res := WmValue(0) for d := wm.log - 1; d >= 0; d-- { f := (xorVal>>d)&1 == 1 l0, r0 := wm.bv[d].Rank(start, false), wm.bv[d].Rank(end, false) c := int32(0) if f { c = (end - start) - (r0 - l0) } else { c = r0 - l0 } if count+c > k { if !f { start, end = l0, r0 } else { start += wm.mid[d] - l0 end += wm.mid[d] - r0 } } else { var s WmSum if f { s = wm._get(d, start+wm.mid[d]-l0, end+wm.mid[d]-r0) } else { s = wm._get(d, l0, r0) } count += c sum = wm.op(sum, s) res |= 1 << d if !f { start += wm.mid[d] - l0 end += wm.mid[d] - r0 } else { start, end = l0, r0 } } } sum = wm.op(sum, wm._get(0, start, start+k-count)) if wm.compress { res = wm.key[res] } return res, sum } // upper: 向上取中位数还是向下取中位数. func (wm *WaveletMatrixWithSum) Median(start, end int32, upper bool, xorVal WmValue) WmValue { n := end - start var k int32 if upper { k = n / 2 } else { k = (n - 1) / 2 } return wm.Kth(start, end, k, xorVal) } func (wm *WaveletMatrixWithSum) SumAll(start, end int32) WmSum { return wm._get(wm.log, start, end) } // 使得predicate(count, sum)为true的最大的(count, sum). func (wm *WaveletMatrixWithSum) MaxRight(predicate func(int32, WmSum) bool, start, end int32, xorVal WmValue) (int32, WmSum) { if xorVal != 0 { if !wm.setLog { panic("log should be set when xor is used") } } if start == end { return end - start, wm.e() } if s := wm._get(wm.log, start, end); predicate(end-start, s) { return end - start, s } count := int32(0) sum := wm.e() for d := wm.log - 1; d >= 0; d-- { f := (xorVal>>d)&1 == 1 l0, r0 := wm.bv[d].Rank(start, false), wm.bv[d].Rank(end, false) c := int32(0) if f { c = (end - start) - (r0 - l0) } else { c = (r0 - l0) } var s WmSum if f { s = wm._get(d, start+wm.mid[d]-l0, end+wm.mid[d]-r0) } else { s = wm._get(d, l0, r0) } if tmp := wm.op(sum, s); predicate(count+c, tmp) { count += c sum = tmp if f { start, end = l0, r0 } else { start += wm.mid[d] - l0 end += wm.mid[d] - r0 } } else { if !f { start, end = l0, r0 } else { start += wm.mid[d] - l0 end += wm.mid[d] - r0 } } } k := wm.binarySearch(func(k int32) bool { return predicate(count+k, wm.op(sum, wm._get(0, start, start+k))) }, 0, end-start) count += k sum = wm.op(sum, wm._get(0, start, start+k)) return count, sum } // [start, end) 中小于等于 x 的数中最大的数 // // 如果不存在则返回-INF func (wm *WaveletMatrixWithSum) Floor(start, end int32, x WmValue, xor WmValue) WmValue { less := wm.CountPrefix(start, end, x, xor) if less == 0 { return -INF } res := wm.Kth(start, end, less-1, xor) return res } // [start, end) 中大于等于 x 的数中最小的数 // // 如果不存在则返回INF func (wm *WaveletMatrixWithSum) Ceil(start, end int32, x WmValue, xor WmValue) int { less := wm.CountPrefix(start, end, x, xor) if less == end-start { return INF } res := wm.Kth(start, end, less, xor) return res } func (wm *WaveletMatrixWithSum) CountSegments(segments [][2]int32, a, b WmValue, xorVal WmValue) int32 { res := int32(0) for _, seg := range segments { res += wm.CountRange(seg[0], seg[1], a, b, xorVal) } return res } func (wm *WaveletMatrixWithSum) KthSegments(segments [][2]int32, k int32, xorVal WmValue) WmValue { totalLen := int32(0) for _, seg := range segments { totalLen += seg[1] - seg[0] } count := int32(0) res := WmValue(0) for d := wm.log - 1; d >= 0; d-- { f := (xorVal>>d)&1 == 1 c := int32(0) for _, seg := range segments { l0, r0 := wm.bv[d].Rank(seg[0], false), wm.bv[d].Rank(seg[1], false) if f { c += (seg[1] - seg[0]) - (r0 - l0) } else { c += r0 - l0 } } if count+c > k { for _, seg := range segments { l0, r0 := wm.bv[d].Rank(seg[0], false), wm.bv[d].Rank(seg[1], false) if !f { seg[0], seg[1] = l0, r0 } else { seg[0] += wm.mid[d] - l0 seg[1] += wm.mid[d] - r0 } } } else { count += c res |= 1 << d for _, seg := range segments { l0, r0 := wm.bv[d].Rank(seg[0], false), wm.bv[d].Rank(seg[1], false) if f { seg[0], seg[1] = l0, r0 } else { seg[0] += wm.mid[d] - l0 seg[1] += wm.mid[d] - r0 } } } } if wm.compress { res = wm.key[res] } return res } func (wm *WaveletMatrixWithSum) KthValueAndSumSegments(segments [][2]int32, k int32, xorVal WmValue) (WmValue, WmSum) { if xorVal != 0 { if !wm.setLog { panic("log should be set when xor is used") } } totalLen := int32(0) for _, seg := range segments { totalLen += seg[1] - seg[0] } if k >= totalLen { return -1, wm.SumAllSegments(segments) } count := int32(0) sum := wm.e() res := WmValue(0) for d := wm.log - 1; d >= 0; d-- { f := (xorVal>>d)&1 == 1 c := int32(0) for _, seg := range segments { l0, r0 := wm.bv[d].Rank(seg[0], false), wm.bv[d].Rank(seg[1], false) if f { c += (seg[1] - seg[0]) - (r0 - l0) } else { c += r0 - l0 } } if count+c > k { for _, seg := range segments { l0, r0 := wm.bv[d].Rank(seg[0], false), wm.bv[d].Rank(seg[1], false) if !f { seg[0], seg[1] = l0, r0 } else { seg[0] += wm.mid[d] - l0 seg[1] += wm.mid[d] - r0 } } } else { count += c res |= 1 << d for _, seg := range segments { l0, r0 := wm.bv[d].Rank(seg[0], false), wm.bv[d].Rank(seg[1], false) var s WmSum if f { s = wm._get(d, seg[0]+wm.mid[d]-l0, seg[1]+wm.mid[d]-r0) } else { s = wm._get(d, l0, r0) } sum = wm.op(sum, s) if !f { seg[0] += wm.mid[d] - l0 seg[1] += wm.mid[d] - r0 } else { seg[0], seg[1] = l0, r0 } } } } for _, seg := range segments { t := min32(seg[1]-seg[0], k-count) sum = wm.op(sum, wm._get(0, seg[0], seg[0]+t)) count += t } if wm.compress { res = wm.key[res] } return res, sum } func (wm *WaveletMatrixWithSum) MedianSegments(segments [][2]int32, upper bool, xorVal WmValue) WmValue { n := int32(0) for _, seg := range segments { n += seg[1] - seg[0] } var k int32 if upper { k = n / 2 } else { k = (n - 1) / 2 } return wm.KthSegments(segments, k, xorVal) } func (wm *WaveletMatrixWithSum) SumAllSegments(segments [][2]int32) WmSum { sum := wm.e() for _, seg := range segments { sum = wm.op(sum, wm._get(wm.log, seg[0], seg[1])) } return sum } func (wm *WaveletMatrixWithSum) _prefixSumSegments(segments [][2]int32, k int32, xor WmValue) WmSum { _, sum := wm.KthValueAndSumSegments(segments, k, xor) return sum } func (wm *WaveletMatrixWithSum) _get(d, l, r int32) WmSum { return wm.op(wm.inv(wm.presum[d][l]), wm.presum[d][r]) } func (wm *WaveletMatrixWithSum) argSort(nums []WmValue) []int32 { order := make([]int32, len(nums)) for i := range order { order[i] = int32(i) } sort.Slice(order, func(i, j int) bool { return nums[order[i]] < nums[order[j]] }) return order } func (wm *WaveletMatrixWithSum) maxs(nums []WmValue) WmValue { res := nums[0] for _, v := range nums { if v > res { res = v } } return res } func (wm *WaveletMatrixWithSum) lowerBound(nums []WmValue, target WmValue) WmValue { left, right := int32(0), int32(len(nums)-1) for left <= right { mid := (left + right) >> 1 if nums[mid] < target { left = mid + 1 } else { right = mid - 1 } } return WmValue(left) } func (wm *WaveletMatrixWithSum) binarySearch(f func(int32) bool, ok, ng int32) int32 { for abs32(ok-ng) > 1 { x := (ok + ng) >> 1 if f(x) { ok = x } else { ng = x } } return ok } func abs(x int) int { if x < 0 { return -x } return x } func abs32(x int32) int32 { if x < 0 { return -x } return x } func min32(a, b int32) int32 { if a < b { return a } return b } func min(a, b int) int { if a < b { return a } return b } type BitVector struct { bits []uint64 preSum []int32 } func NewBitVector(n int32) *BitVector { return &BitVector{bits: make([]uint64, n>>6+1), preSum: make([]int32, n>>6+1)} } func (bv *BitVector) Set(i int32) { bv.bits[i>>6] |= 1 << (i & 63) } func (bv *BitVector) Build() { for i := 0; i < len(bv.bits)-1; i++ { bv.preSum[i+1] = bv.preSum[i] + int32(bits.OnesCount64(bv.bits[i])) } } func (bv *BitVector) Rank(k int32, f bool) int32 { m, s := bv.bits[k>>6], bv.preSum[k>>6] res := s + int32(bits.OnesCount64(m&((1<<(k&63))-1))) if f { return res } return k - res }