java
复制代码
class StreamRank {
TreeNode root;
public StreamRank() {
root = null;
}
public void track(int x) {
if (root == null) {
root = new TreeNode();
root.val = x;
root.num = 1;
return;
}
// 找到值为x的节点,没找到x则需要找到x应该插入的节点位置
TreeNode node = findX(x, root);
// 找到了值为x的节点
if (node.val == x) {
node.num += 1;
return;
}
// 没有找到需要将值为x的新节点插入到树中
TreeNode newNode = new TreeNode();
newNode.val = x;
newNode.num = 1;
if (node.val > x) {
node.left = newNode;
} else {
node.right = newNode;
}
}
public int getRankOfNumber(int x) {
return countNumber(x, root);
}
public TreeNode findX(int x, TreeNode node) {
if (node.val == x) {
return node;
}
if (node.val > x) {
if (node.left == null) {
return node;
}
return findX(x, node.left);
} else {
if (node.right == null) {
return node;
}
return findX(x, node.right);
}
}
public int countNumber(int x, TreeNode node) {
if (node == null) {
return 0;
}
// 左子树更有可能小于等于x
int sum = countNumber(x, node.left);
if (node.val <= x) {
sum = sum + node.num + countNumber(x, node.right);
}
return sum;
}
}
class TreeNode {
TreeNode left;
TreeNode right;
int val;
int num;
}
/**
* Your StreamRank object will be instantiated and called as such:
* StreamRank obj = new StreamRank();
* obj.track(x);
* int param_2 = obj.getRankOfNumber(x);
*/