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package class47;
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// 只支持单点增加 + 范围查询的动态开点线段树（累加和）
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public class Code01_DynamicSegmentTree {
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public static class Node {
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public int sum;
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public Node left;
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public Node right;
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}
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// arr[0] -> 1
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// 线段树，从1开始下标!
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public static class DynamicSegmentTree {
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public Node root;
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public int size;
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public DynamicSegmentTree(int max) {
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root = new Node();
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size = max;
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}
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// 下标i这个位置的数，增加v
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public void add(int i, int v) {
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add(root, 1, size, i, v);
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}
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// c-> cur 当前节点！表达的范围 l~r
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// i位置的数，增加v
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// 潜台词！i一定在l~r范围上！
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private void add(Node c, int l, int r, int i, int v) {
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if (l == r) {
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c.sum += v;
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} else { // l~r 还可以划分
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int mid = (l + r) / 2;
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if (i <= mid) { // l ~ mid
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if (c.left == null) {
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c.left = new Node();
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}
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add(c.left, l, mid, i, v);
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} else { // mid + 1 ~ r
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if (c.right == null) {
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c.right = new Node();
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}
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add(c.right, mid + 1, r, i, v);
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}
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c.sum = (c.left != null ? c.left.sum : 0) + (c.right != null ? c.right.sum : 0);
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}
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}
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// s~e范围的累加和，告诉我！
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public int query(int s, int e) {
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return query(root, 1, size, s, e);
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}
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// 当前节点c，表达的范围l~r
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// 收到了一个任务，s~e这个任务！
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// s~e这个任务，影响了多少l~r范围的数，把答案返回！
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private int query(Node c, int l, int r, int s, int e) {
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if (c == null) {
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return 0;
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}
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if (s <= l && r <= e) { // 3~6 1~100任务
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return c.sum;
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}
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// 有影响，但又不是全影响
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// l ~ r
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// l~mid mid+1~r
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int mid = (l + r) / 2;
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// 1~100
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// 1~50 51 ~ 100
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// 任务 s~e 53~76
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if (e <= mid) {
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return query(c.left, l, mid, s, e);
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} else if (s > mid) {
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return query(c.right, mid + 1, r, s, e);
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} else {
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return query(c.left, l, mid, s, e) + query(c.right, mid + 1, r, s, e);
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}
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}
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}
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public static class Right {
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public int[] arr;
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public Right(int size) {
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arr = new int[size + 1];
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}
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public void add(int i, int v) {
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arr[i] += v;
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}
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public int query(int s, int e) {
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int sum = 0;
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for (int i = s; i <= e; i++) {
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sum += arr[i];
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}
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return sum;
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}
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}
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public static void main(String[] args) {
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int size = 10000;
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int testTime = 50000;
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int value = 500;
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DynamicSegmentTree dst = new DynamicSegmentTree(size);
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Right right = new Right(size);
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System.out.println("测试开始");
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for (int k = 0; k < testTime; k++) {
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if (Math.random() < 0.5) {
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int i = (int) (Math.random() * size) + 1;
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int v = (int) (Math.random() * value);
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dst.add(i, v);
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right.add(i, v);
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} else {
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int a = (int) (Math.random() * size) + 1;
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int b = (int) (Math.random() * size) + 1;
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int s = Math.min(a, b);
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int e = Math.max(a, b);
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int ans1 = dst.query(s, e);
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int ans2 = right.query(s, e);
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if (ans1 != ans2) {
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System.out.println("出错了!");
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System.out.println(ans1);
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System.out.println(ans2);
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}
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}
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}
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System.out.println("测试结束");
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}
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}
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