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Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.
The update(i, val) function modifies nums by updating the element at index i to val.
Example:
Given nums = [1, 3, 5] sumRange(0, 2) -> 9 update(1, 2) sumRange(0, 2) -> 8
Note:
- The array is only modifiable by the update function.
- You may assume the number of calls to update and sumRangefunction is distributed evenly.
给定一个整数数组 nums，求出数组从索引 i 到 j (i ≤ j) 范围内元素的总和，包含 i, j 两点。
update(i, val) 函数可以通过将下标为 i 的数值更新为 val，从而对数列进行修改。
示例:
Given nums = [1, 3, 5] sumRange(0, 2) -> 9 update(1, 2) sumRange(0, 2) -> 8
说明:
- 数组仅可以在 update 函数下进行修改。
- 你可以假设 update 函数与 sumRange 函数的调用次数是均匀分布的。
192ms
1 class NumArray { 2 private class Node { 3 var val: Int 4 var sum: Int 5 var count: Int 6 var left: Node?, right: Node? 7 init(val: Int, left: Node?, right: Node?) { 8 self.val = val 9 sum = val 10 count = 1 11 if let left = left { 12 self.left = left 13 sum += left.sum 14 count += left.count 15 } 16 if let right = right { 17 self.right = right 18 sum += right.sum 19 count += right.count 20 } 21 } 22 } 23 24 private var root: Node? 25 26 init(_ nums: [Int]) { 27 func makeTree(li: Int, ui: Int) -> Node? { 28 if li <= ui { 29 let mid = li + (ui - li) / 2 30 let left = makeTree(li: li, ui: mid - 1) 31 let right = makeTree(li: mid + 1, ui: ui) 32 return Node(val: nums[mid], left: left, right: right) 33 } 34 return nil 35 } 36 root = makeTree(li: 0, ui: nums.count - 1) 37 } 38 39 func update(_ i: Int, _ val: Int) { 40 if let root = root { 41 update(node: root, i: i, val: val) 42 } 43 } 44 45 private func update(node: Node, i: Int, val: Int) { 46 if let left = node.left, i < left.count { 47 let prevLeftSum = left.sum 48 update(node: left, i: i, val: val) 49 node.sum = node.sum - prevLeftSum + left.sum 50 } else if i == (node.left?.count ?? 0) { 51 node.sum = node.sum - node.val + val 52 node.val = val 53 } else if let right = node.right { 54 let prevRightSum = right.sum 55 update(node: right, i: i - (node.left?.count ?? 0) - 1, val: val) 56 node.sum = node.sum - prevRightSum + right.sum 57 } 58 } 59 60 func sumRange(_ i: Int, _ j: Int) -> Int { 61 if let root = root { 62 return sum(node: root, count: j + 1) - sum(node: root, count: i) 63 } 64 return 0 65 } 66 67 private func sum(node: Node, count: Int) -> Int { 68 if count == node.count { 69 return node.sum 70 } 71 72 var s = 0 73 var c = count 74 if c > 0, let left = node.left { 75 let lc = min(count, left.count) 76 s += sum(node: left, count: lc) 77 c -= lc 78 } 79 if c > 0 { 80 s += node.val 81 c -= 1 82 } 83 if c > 0, let right = node.right { 84 s += sum(node: right, count: c) 85 } 86 return s 87 } 88 89 func inOrderPrint() { 90 inOrderPrint(node: root) 91 print() 92 } 93 94 private func inOrderPrint(node: Node?) { 95 if let node = node { 96 inOrderPrint(node: node.left) 97 print((node.val, node.count, node.sum), terminator: " ") 98 inOrderPrint(node: node.right) 99 } 100 } 101 }
412ms
1 class NumArray { 2 3 var tree : [Int] 4 var size : Int 5 6 7 init(_ nums: [Int]) { 8 size = nums.count 9 tree = Array(repeating: 0, count: size << 2) 10 11 if size != 0 { 12 build(1, size, 1, nums) 13 } 14 15 } 16 17 func build(_ l :Int, _ r : Int, _ rt : Int, _ nums : [Int]){ 18 if l == r { 19 tree[rt] = nums[l-1] 20 return 21 } 22 23 let m = (l + r) >> 1 24 build(l, m, rt<<1, nums) 25 build(m+1, r, rt<<1|1, nums) 26 pushup(rt) 27 } 28 29 func pushup(_ rt : Int) { 30 tree[rt] = tree[rt<<1] + tree[rt << 1|1] 31 } 32 33 func update(_ p : Int, _ val : Int, _ l : Int, _ r : Int, _ rt : Int){ 34 if l == r { 35 tree[rt] = val 36 return 37 } 38 39 let m = (l + r) >> 1 40 if p <= m { 41 update(p, val, l, m, rt << 1) 42 }else { 43 update(p, val, m+1, r, rt << 1 | 1) 44 } 45 46 pushup(rt) 47 } 48 49 func query(_ L : Int, _ R : Int, _ l : Int, _ r : Int, _ rt : Int) -> Int { 50 if L <= l && r <= R { 51 return tree[rt] 52 } 53 54 let m = (l + r) >> 1 55 var ans = 0 56 if L <= m { 57 ans += query(L, R, l, m, rt<<1) 58 } 59 if R >= m+1 { 60 ans += query(L, R, m+1, r, rt << 1|1) 61 } 62 63 return ans 64 } 65 66 func update(_ i: Int, _ val: Int) { 67 update(i+1, val, 1, size, 1) 68 69 70 } 71 72 func sumRange(_ i: Int, _ j: Int) -> Int { 73 return query(i+1, j+1, 1, size, 1) 74 } 75 } 76 77 /** 78 * Your NumArray object will be instantiated and called as such: 79 * let obj = NumArray(nums) 80 * obj.update(i, val) 81 * let ret_2: Int = obj.sumRange(i, j) 82 */
2580ms
1 class NumArray { 2 3 var _nums : [Int] 4 var sums : [Int] 5 var changes : [Int : Int] 6 7 init(_ nums: [Int]) { 8 _nums = nums 9 sums = nums 10 changes = [Int : Int]() 11 12 if nums.isEmpty { 13 return 14 } 15 16 for i in 1..<nums.count { 17 sums[i] += sums[i-1] 18 } 19 20 } 21 22 func update(_ i: Int, _ val: Int) { 23 if i >= _nums.count { 24 return 25 } 26 let c = val - _nums[i] 27 _nums[i] = val 28 if changes[i] != nil { 29 changes[i]! += c 30 }else { 31 changes[i] = c 32 } 33 34 if !_nums.isEmpty && changes.count > _nums.count / 2 { 35 sums = _nums 36 for i in 1..<_nums.count { 37 sums[i] += sums[i-1] 38 } 39 changes.removeAll() 40 } 41 42 43 } 44 45 func sumRange(_ i: Int, _ j: Int) -> Int { 46 var res = sums[j] 47 if i > 0 { 48 res -= sums[i-1] 49 } 50 for dic in changes { 51 if dic.key <= j && dic.key >= i { 52 res += dic.value 53 } 54 } 55 return res 56 } 57 } 58 59 /** 60 * Your NumArray object will be instantiated and called as such: 61 * let obj = NumArray(nums) 62 * obj.update(i, val) 63 * let ret_2: Int = obj.sumRange(i, j) 64 */ 65
4152ms
1 class NumArray { 2 3 private var sums: [Int] = [] 4 private var nums: [Int] = [] 5 6 init(_ nums: [Int]) { 7 guard !nums.isEmpty else { 8 return 9 } 10 11 var sums = Array(repeating: 0, count: nums.count) 12 sums[0] = nums[0] 13 for index in 1..<nums.count { 14 let num = nums[index] 15 sums[index] = sums[index - 1] + num 16 } 17 18 self.sums = sums 19 self.nums = nums 20 } 21 22 func update(_ i: Int, _ val: Int) { 23 guard i < nums.count else { 24 return 25 } 26 27 let offset = val - nums[i] 28 guard offset != 0 else { 29 return 30 } 31 32 for index in i..<nums.count { 33 sums[index] += offset 34 } 35 36 nums[i] = val 37 } 38 39 func sumRange(_ i: Int, _ j: Int) -> Int { 40 if i == 0 { 41 return sums[j] 42 } else { 43 return sums[j] - sums[i - 1] 44 } 45 } 46 } 47 48 /** 49 * Your NumArray object will be instantiated and called as such: 50 * let obj = NumArray(nums) 51 * obj.update(i, val) 52 * let ret_2: Int = obj.sumRange(i, j) 53 */
4724ms
1 class NumArray { 2 3 var nums: [Int] 4 var sumArray = [Int]() 5 6 init(_ nums: [Int]) { 7 self.nums = nums 8 sumArray = nums 9 if nums.count > 1 { 10 for i in 1 ..< nums.count { 11 sumArray[i] = sumArray[i - 1] + nums[i] 12 } 13 } 14 } 15 16 func update(_ i: Int, _ val: Int) { 17 let diff = val - nums[i] 18 self.nums[i] = val 19 for j in i ..< nums.count { 20 sumArray[j] += diff 21 } 22 } 23 24 func sumRange(_ i: Int, _ j: Int) -> Int { 25 if i == 0 { 26 return sumArray[j] 27 } else { 28 return sumArray[j] - sumArray[i - 1] 29 } 30 31 } 32 } 33 34 /** 35 * Your NumArray object will be instantiated and called as such: 36 * let obj = NumArray(nums) 37 * obj.update(i, val) 38 * let ret_2: Int = obj.sumRange(i, j) 39 */ 40