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mirror of https://git.sb/baoshuo/OI-codes.git synced 2024-11-08 13:38:48 +00:00

B3642 二叉树的遍历

https://www.luogu.com.cn/record/169648364
This commit is contained in:
Baoshuo Ren 2024-07-31 11:43:16 +08:00
parent af29bbe0c9
commit 96f8d117e2
Signed by: baoshuo
GPG Key ID: 00CB9680AB29F51A

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Luogu/B3642/B3642.cpp Normal file
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#include <iostream>
#include <algorithm>
#include <iterator>
using std::cin;
using std::cout;
const char endl = '\n';
const int N = 1e6 + 5;
int n;
int lch[N], rch[N];
int cnt_pre, pre[N],
cnt_in, in[N],
cnt_post, post[N];
void pre_order(int u) {
pre[++cnt_pre] = u;
if (lch[u]) pre_order(lch[u]);
if (rch[u]) pre_order(rch[u]);
}
void in_order(int u) {
if (lch[u]) in_order(lch[u]);
in[++cnt_in] = u;
if (rch[u]) in_order(rch[u]);
}
void post_order(int u) {
if (lch[u]) post_order(lch[u]);
if (rch[u]) post_order(rch[u]);
post[++cnt_post] = u;
}
int main() {
std::ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> lch[i] >> rch[i];
}
pre_order(1);
in_order(1);
post_order(1);
std::copy_n(pre + 1, n, std::ostream_iterator<int>(cout, " "));
cout << endl;
std::copy_n(in + 1, n, std::ostream_iterator<int>(cout, " "));
cout << endl;
std::copy_n(post + 1, n, std::ostream_iterator<int>(cout, " "));
cout << endl;
return 0;
}