1099. Build A Binary Search Tree

构造树的结构，记录每个节点左右的孩子节点数，从而判断其数值的大小位置。

#include <iostream>#include <algorithm>#include <queue>#include <stdio.h>using namespace std;struct Info{    int left;    int leftNodes;    int right;    int rightNodes;    int total;    int value;};int n;int *num;Info *tree;void build(int root, int start){    if(root == -1)        return;    tree[root].value = num[tree[root].leftNodes + start];    build(tree[root].left, start);    build(tree[root].right, 1+tree[root].leftNodes + start);}int calcunums(int root){    if(root == -1)        return 0;    if(tree[root].left == -1)        tree[root].leftNodes = 0;    else        tree[root].leftNodes = calcunums(tree[root].left)+1;    if(tree[root].right == -1)        tree[root].rightNodes = 0;    else        tree[root].rightNodes = calcunums(tree[root].right)+1;    tree[root].total = tree[root].leftNodes + tree[root].rightNodes;    return tree[root].total;}int main(){    scanf("%d", &n);    num = new int[n];    tree = new Info[n];    for(int i = 0; i < n; i++)        scanf("%d %d", &(tree[i].left), &(tree[i].right));    for(int i = 0; i < n; i++)        scanf("%d", num+i);    sort(num, num+n);    calcunums(0);    build(0, 0);    bool first = true;    queue<Info> output;    Info info;    output.push(tree[0]);    while(!output.empty())    {        info = output.front();        output.pop();        if(first)            cout << info.value;        else            cout << " " << info.value;        first = false;        if(info.left != -1)            output.push(tree[info.left]);        if(info.right != -1)            output.push(tree[info.right]);    }    return 0;}