package main import ( "bufio" "fmt" "math" "math/bits" "os" "sort" ) func main() { // demo() // test() // testTime() 区间前驱后继() } // TODO:范围问题 // 4 // 1 4 2 3 // 4 // 1 3 4 // 1 4 9 // 1 4 2 // 2 3 3 // 0 5 0 1 func 区间前驱后继() { in := bufio.NewReader(os.Stdin) out := bufio.NewWriter(os.Stdout) defer out.Flush() var n int32 fmt.Fscan(in, &n) nums := make([]int, n) for i := int32(0); i < n; i++ { fmt.Fscan(in, &nums[i]) } wm := NewWaveletMatrixStatic(int32(len(nums)), func(i int32) int { return int(nums[i]) }, maxs(nums)) var q int32 fmt.Fscan(in, &q) for i := int32(0); i < q; i++ { var start, end int32 var x int fmt.Fscan(in, &start, &end, &x) start-- newX := x res := math.MaxInt floor, ok := wm.Floor(start, end, newX) if ok { res = min(res, abs(x-floor)) } ceil, ok := wm.Ceil(start, end, newX) if ok { res = min(res, abs(x-ceil)) } fmt.Fprintln(out, res) } } func demo() { nums := []int{3, 1, 4, 1, 5, 9, 2, 6} wm := NewWaveletMatrixStatic(int32(len(nums)), func(i int32) int { return nums[i] }, maxs(nums)+1) fmt.Println(wm.PrefixCount(10, 2)) fmt.Println(wm.Kth(0, 2)) fmt.Println(wm.KthSmallest(1, 4, 2)) fmt.Println(wm.RangeFreq(0, 8, 1, 4)) fmt.Println(wm.RangeCount(0, 8, 1)) fmt.Println(wm.RangeCount(0, 8, 2)) fmt.Println(wm.Floor(0, 8, 3)) fmt.Println(wm.Ceil(0, 8, 3)) fmt.Println(wm.Lower(0, 8, 3)) fmt.Println(wm.Higher(0, 8, 3)) fmt.Println(wm.Higher(0, 8, 1)) } // 将nums中的元素进行离散化,返回新的数组和对应的原始值. // origin[newNums[i]] == nums[i] func DiscretizeFast(nums []int) (newNums []int32, origin []int) { newNums = make([]int32, len(nums)) origin = make([]int, 0, len(newNums)) order := argSort(int32(len(nums)), func(i, j int32) bool { return nums[i] < nums[j] }) for _, i := range order { if len(origin) == 0 || origin[len(origin)-1] != nums[i] { origin = append(origin, nums[i]) } newNums[i] = int32(len(origin) - 1) } origin = origin[:len(origin):len(origin)] return } func BisectLeft(nums []int, target int) int32 { 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 left } func argSort(n int32, less func(i, j int32) bool) []int32 { order := make([]int32, n) for i := range order { order[i] = int32(i) } sort.Slice(order, func(i, j int) bool { return less(order[i], order[j]) }) return order } func maxs(nums []int) int { max := nums[0] for _, num := range nums { if num > max { max = num } } return max } func maxs32(nums []int32) int32 { max := nums[0] for _, num := range nums { if num > max { max = num } } return max } // 维护[0,maxValue]. type WaveletMatrixStatic struct { size int32 maxValue int bitLen int32 mid []int32 bv []*bitVector } type topKPair = struct { value int count int32 } func NewWaveletMatrixStatic(n int32, f func(int32) int, maxValue int) *WaveletMatrixStatic { if maxValue <= 0 { maxValue = 1 } res := &WaveletMatrixStatic{ size: n, maxValue: maxValue, bitLen: int32(bits.Len(uint(maxValue))), } res.mid = make([]int32, res.bitLen) res.bv = make([]*bitVector, res.bitLen) if n > 0 { res._build(n, f) } return res } func (wm *WaveletMatrixStatic) PrefixCount(end int32, x int) int32 { if end > wm.size { end = wm.size } if end <= 0 { return 0 } start := int32(0) mid := wm.mid for bit := wm.bitLen - 1; bit >= 0; bit-- { if x>>bit&1 == 1 { start = wm.bv[bit].Count1(start) + mid[bit] end = wm.bv[bit].Count1(end) + mid[bit] } else { start = wm.bv[bit].Count0(start) end = wm.bv[bit].Count0(end) } } return end - start } func (wm *WaveletMatrixStatic) RangeCount(start, end int32, x int) int32 { if start < 0 { start = 0 } if end > wm.size { end = wm.size } if start >= end { return 0 } same, _, _ := wm.CountAll(start, end, x) return same } func (wm *WaveletMatrixStatic) RangeFreq(start, end int32, floor, higher int) int32 { if floor >= higher { return 0 } if start < 0 { start = 0 } if end > wm.size { end = wm.size } if start >= end { return 0 } return wm.CountLess(start, end, higher) - wm.CountLess(start, end, floor) } // 返回第k个x所在的位置. func (wm *WaveletMatrixStatic) Kth(k int32, x int) int32 { s := int32(0) for bit := wm.bitLen - 1; bit >= 0; bit-- { if x>>bit&1 == 1 { s = wm.bv[bit].Count0(wm.size) + wm.bv[bit].Count1(s) } else { s = wm.bv[bit].Count0(s) } } s += k for bit := int32(0); bit < wm.bitLen; bit++ { if x>>bit&1 == 1 { s = wm.bv[bit].Kth1(s - wm.bv[bit].Count0(wm.size)) } else { s = wm.bv[bit].Kth0(s) } } return s } func (wm *WaveletMatrixStatic) KthSmallest(start, end int32, k int32) int { if k < 0 || k >= end-start { return -1 } res := 0 for bit := wm.bitLen - 1; bit >= 0; bit-- { l0, r0 := wm.bv[bit].Count0(start), wm.bv[bit].Count0(end) if c := r0 - l0; c <= k { res |= 1 << bit k -= c start += wm.mid[bit] - l0 end += wm.mid[bit] - r0 } else { start, end = l0, r0 } } return res } func (wm *WaveletMatrixStatic) KthSmallestIndex(start, end int32, k int32) int32 { if k < 0 || k >= end-start { return -1 } val := 0 for i := wm.bitLen - 1; i >= 0; i-- { numOfZeroBegin := wm.bv[i].Count0(start) numOfZeroEnd := wm.bv[i].Count0(end) numOfZero := numOfZeroEnd - numOfZeroBegin bit := 0 if k >= numOfZero { bit = 1 } if bit == 1 { k -= numOfZero start = wm.mid[i] + start - numOfZeroBegin end = wm.mid[i] + end - numOfZeroEnd } else { start = numOfZeroBegin end = numOfZeroBegin + numOfZero } val = (val << 1) | bit } left := int32(0) for i := wm.bitLen - 1; i >= 0; i-- { bit := int8((val >> i) & 1) left = wm.bv[i].Count(left, bit) if bit == 1 { left += wm.mid[i] } } rank := start + k - left return wm.Kth(rank, val) } func (wm *WaveletMatrixStatic) KthLargest(start, end int32, k int32) int { return wm.KthSmallest(start, end, end-start-k-1) } func (wm *WaveletMatrixStatic) KthLargestIndex(start, end int32, k int32) int32 { return wm.KthSmallestIndex(start, end, end-start-k-1) } func (wm *WaveletMatrixStatic) Floor(start, end int32, x int) (int, bool) { same, less, _ := wm.CountAll(start, end, x) if same > 0 { return x, true } if less == 0 { return -1, false } return wm.KthSmallest(start, end, less-1), true } func (wm *WaveletMatrixStatic) Lower(start, end int32, x int) (int, bool) { less := wm.CountLess(start, end, x) if less == 0 { return -1, false } return wm.KthSmallest(start, end, less-1), true } func (wm *WaveletMatrixStatic) Ceil(start, end int32, x int) (int, bool) { same, less, _ := wm.CountAll(start, end, x) if same > 0 { return x, true } if less == end-start { return -1, false } return wm.KthSmallest(start, end, less), true } func (wm *WaveletMatrixStatic) Higher(start, end int32, x int) (int, bool) { less := wm.CountLess(start, end, x+1) if less == end-start { return -1, false } return wm.KthSmallest(start, end, less), true } // 返回[start, end)中等于x的个数,小于x的个数,大于x的个数. func (wm *WaveletMatrixStatic) CountAll(start, end int32, x int) (same, less, more int32) { if start < 0 { start = 0 } if end > wm.size { end = wm.size } if start >= end { return 0, 0, 0 } if x > wm.maxValue { return 0, end - start, 0 } num := end - start for i := wm.bitLen - 1; i >= 0 && start < end; i-- { bit := x >> i & 1 rank0Begin := wm.bv[i].Count0(start) rank0End := wm.bv[i].Count0(end) rank1Begin := start - rank0Begin rank1End := end - rank0End if bit == 1 { less += rank0End - rank0Begin start = wm.mid[i] + rank1Begin end = wm.mid[i] + rank1End } else { more += rank1End - rank1Begin start = rank0Begin end = rank0End } } same = num - less - more return } func (wm *WaveletMatrixStatic) Get(index int32) int { if index < 0 { index += wm.size } res := 0 for bit := wm.bitLen - 1; bit >= 0; bit-- { if wm.bv[bit].Get(index) { res |= 1 << bit index = wm.bv[bit].Count1(index) + wm.mid[bit] } else { index = wm.bv[bit].Count0(index) } } return res } // 区间[start, end)中小于x的元素个数. func (wm *WaveletMatrixStatic) CountLess(start, end int32, x int) int32 { res := int32(0) for bit := wm.bitLen - 1; bit >= 0; bit-- { l0, r0 := wm.bv[bit].Count0(start), wm.bv[bit].Count0(end) if x>>bit&1 == 1 { res += r0 - l0 start += wm.mid[bit] - l0 end += wm.mid[bit] - r0 } else { start, end = l0, r0 } } return res } // 区间[start, end)中大于x的元素个数. func (wm *WaveletMatrixStatic) CountMore(start, end int32, x int) int32 { return end - start - wm.CountLess(start, end, x+1) } func (wm *WaveletMatrixStatic) CountSame(start, end int32, x int) int32 { same, _, _ := wm.CountAll(start, end, x) return same } func (wm *WaveletMatrixStatic) Len() int32 { return wm.size } func (wm *WaveletMatrixStatic) _build(n int32, f func(int32) int) { data := make([]int, n) for i := int32(0); i < n; i++ { data[i] = f(i) } zero, one := make([]int, n), make([]int, n) for bit := wm.bitLen - 1; bit >= 0; bit-- { wm.bv[bit] = newBitVector(n) v := wm.bv[bit] p, q := int32(0), int32(0) for i, e := range data { if e>>bit&1 == 1 { v.Set(int32(i)) one[q] = e q++ } else { zero[p] = e p++ } } v.Build() wm.mid[bit] = p zero, data = data, zero copy(data[p:], one[:q]) } } type bitVector struct { n int32 size int32 bit []uint64 preSum []int32 } func newBitVector(n int32) *bitVector { size := (n + 63) >> 6 bit := make([]uint64, size+1) preSum := make([]int32, size+1) return &bitVector{n: n, size: size, bit: bit, preSum: preSum} } func (bv *bitVector) Set(i int32) { bv.bit[i>>6] |= 1 << (i & 63) } func (bv *bitVector) Build() { for i := int32(0); i < bv.size; i++ { bv.preSum[i+1] = bv.preSum[i] + int32(bits.OnesCount64(bv.bit[i])) } } func (bv *bitVector) Get(i int32) bool { return bv.bit[i>>6]>>(i&63)&1 == 1 } func (bv *bitVector) Count0(end int32) int32 { return end - (bv.preSum[end>>6] + int32(bits.OnesCount64(bv.bit[end>>6]&(1<<(end&63)-1)))) } func (bv *bitVector) Count1(end int32) int32 { return bv.preSum[end>>6] + int32(bits.OnesCount64(bv.bit[end>>6]&(1<<(end&63)-1))) } func (bv *bitVector) Count(end int32, value int8) int32 { if value == 1 { return bv.Count1(end) } return end - bv.Count1(end) } func (bv *bitVector) Kth0(k int32) int32 { if k < 0 || bv.Count0(bv.n) <= k { return -1 } l, r := int32(0), bv.size+1 for r-l > 1 { m := (l + r) >> 1 if m<<6-bv.preSum[m] > k { r = m } else { l = m } } indx := l << 6 k -= (l<<6 - bv.preSum[l]) - bv.Count0(indx) l, r = indx, indx+64 for r-l > 1 { m := (l + r) >> 1 if bv.Count0(m) > k { r = m } else { l = m } } return l } // k>=0. func (bv *bitVector) Kth1(k int32) int32 { if k < 0 || bv.Count1(bv.n) <= k { return -1 } l, r := int32(0), bv.size+1 for r-l > 1 { m := (l + r) >> 1 if bv.preSum[m] > k { r = m } else { l = m } } indx := l << 6 k -= bv.preSum[l] - bv.Count1(indx) l, r = indx, indx+64 for r-l > 1 { m := (l + r) >> 1 if bv.Count1(m) > k { r = m } else { l = m } } return l } func (bv *bitVector) Kth(k int32, v int8) int32 { if v == 1 { return bv.Kth1(k) } return bv.Kth0(k) } func (bv *bitVector) GetAll() []bool { res := make([]bool, 0, bv.n) for i := int32(0); i < bv.n; i++ { res = append(res, bv.Get(i)) } return res } func abs(x int) int { if x < 0 { return -x } return x } func min(a, b int) int { if a < b { return a } return b } func max(a, b int) int { if a > b { return a } return b }