[洛谷] [P1305] 新二叉树

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XJB打的非模板

每次搜都搜到底

#include <cstdio>
#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <string>
#include <cstring>
#include <algorithm>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <ctime>
#include <vector>
#include <fstream>
#include <list>
#include <iomanip>
#include <numeric>
using namespace std;
typedef long long ll;

const int MAXN = 1e6 + 10;

char tree[MAXN];

void join(int now, char lson, char rson)
{
    tree[now * 2] = lson;
    tree[now * 2 + 1] = rson;
}

int findt(int now, char val)
{
    if(tree[now] == val)
        return now;
	
	int ans = -1;
    
	if(tree[now] != '*')
    {
        ans = max(ans, findt(now * 2, val) );
        ans = max(ans, findt(now * 2 + 1, val) );
    }

    return ans;
}

void put(int now)
{
    if(tree[now] != '*')
    {
        cout<<tree[now];

        put(now * 2);

        put(now * 2 + 1);
    }
}
int main()
{
    ios::sync_with_stdio(false);

    cin.tie(0);     cout.tie(0);

    int N;

    cin>>N;

    memset(tree, '*', sizeof(tree));

    N--;

    char fat, lson, rson;

    cin>>fat>>lson>>rson;

    tree[1] = fat;

    tree[2] = lson;

    tree[3] = rson;

    while(N--)
    {
        cin>>fat>>lson>>rson;

        join( findt(1, fat), lson, rson);
    }

    put(1);

    return 0;
}