字典树入门

今天先写了01字典树，学习博客

这个01字典树还是很简单的，看看模板就会了

贴一下我的模板

const int maxn = 1e5 + 10;
int n, m, tot;
int trie[32 * maxn][2], num[maxn];
ll val[maxn * 32];

void init()
{
    tot = 1;
    trie[0][0] = trie[0][1] = 0;
}

void insert(ll x)
{
    int u = 0;
    for(int i=32;i>=0;i--)
    {
        int v = (x >> i) & 1;
        if(trie[u][v]==0)
        {
            trie[tot][0] = trie[tot][1] = 0;//初始化
            val[tot] = 0, num[tot] = 0;
            trie[u][v] = tot++;
        }
        u = trie[u][v];
        num[u]++;
    }
    val[u] = x;
}

void update(ll x,int f)
{
    int u = 0;
    for(int i=32;i>=0;i--)
    {
        int v = (x >> i) & 1;
        u = trie[u][v];
        num[u] += f;
    }
}

ll query(ll x)
{
    int u = 0;
    for(int i=32;i>=0;i--)
    {
        int v = (x >> i) & 1;
        if (trie[u][v ^ 1] && num[trie[u][v ^ 1]]) u = trie[u][v ^ 1];
        else u = trie[u][v];
    }
    return val[u] ^ x;
}

然后就是今天写的两个简单的裸题

G - Xor Sum

 HDU - 4825 

#include <cstring>
#include <queue>
#include <cstdlib>
#include <cstdio>
#include <iostream>
#include <string>
#include <bitset>
#include <algorithm>
#include <map>
#include <vector>
#define inf 0x3f3f3f3f
#define inf64 0x3f3f3f3f3f3f3f3f
using namespace std;
typedef long long ll;
const int maxn = 1e5 + 10;
int n, m, tot;
int trie[32 * maxn][2];
ll val[maxn * 32];

void init()
{
    tot = 1;
    trie[0][0] = trie[0][1] = 0;
}

void insert(ll x)
{
    int u = 0;
    for(int i=32;i>=0;i--)
    {
        int v = (x >> i) & 1;
        if(trie[u][v]==0)
        {
            trie[tot][0] = trie[tot][1] = 0;//初始化
            val[tot] = 0;
            trie[u][v] = tot++;
        }
        u = trie[u][v];
    }
    val[u] = x;
}

ll query(ll x)
{
    int u = 0;
    for(int i=32;i>=0;i--)
    {
        int v = (x >> i) & 1;
        if (trie[u][v ^ 1]) u = trie[u][v ^ 1];
        else u = trie[u][v];
    }
    return val[u];
}

int main()
{
    int t;
    scanf("%d", &t);
    for(int cas=1;cas<=t;cas++)
    {
        int n, m;
        init();
        scanf("%d%d", &n, &m);
        for(int i=1;i<=n;i++)
        {
            ll x;
            scanf("%lld", &x);
            insert(x);
        }
        printf("Case #%d:
", cas);
        while(m--)
        {
            ll x;
            scanf("%lld", &x);
            printf("%lld
", query(x));
        }
    }
    return 0;
}

H - Chip Factory

 HDU - 5536 

这个有修改的操作，学习一下

有点卡时间，注意for的优化

#include <cstring>
#include <queue>
#include <cstdlib>
#include <cstdio>
#include <iostream>
#include <string>
#include <bitset>
#include <algorithm>
#include <map>
#include <vector>
#define inf 0x3f3f3f3f
#define inf64 0x3f3f3f3f3f3f3f3f
using namespace std;
typedef long long ll;
const int maxn = 1e5 + 10;
int n, m, tot;
int trie[32 * maxn][2], num[maxn];
ll val[maxn * 32];

void init()
{
    tot = 1;
    trie[0][0] = trie[0][1] = 0;
}

void insert(ll x)
{
    int u = 0;
    for(int i=32;i>=0;i--)
    {
        int v = (x >> i) & 1;
        if(trie[u][v]==0)
        {
            trie[tot][0] = trie[tot][1] = 0;//初始化
            val[tot] = 0, num[tot] = 0;
            trie[u][v] = tot++;
        }
        u = trie[u][v];
        num[u]++;
    }
    val[u] = x;
}

void update(ll x,int f)
{
    int u = 0;
    for(int i=32;i>=0;i--)
    {
        int v = (x >> i) & 1;
        u = trie[u][v];
        num[u] += f;
    }
}

ll query(ll x)
{
    int u = 0;
    for(int i=32;i>=0;i--)
    {
        int v = (x >> i) & 1;
        if (trie[u][v ^ 1] && num[trie[u][v ^ 1]]) u = trie[u][v ^ 1];
        else u = trie[u][v];
    }
    return val[u] ^ x;
}
ll a[maxn];
int main()
{
    int t;
    scanf("%d", &t);
    while(t--)
    {
        int n; init();
        scanf("%d", &n);
        for(int i=1;i<=n;i++)
        {
            scanf("%lld", &a[i]);
            insert(a[i]);
        }
        ll ans = 0;
        for (int i = 1; i <= n; i++) {
            for (int j = i + 1; j <= n; j++) {
                update(a[i], -1), update(a[j], -1);
                ans = max(ans, query(a[i] + a[j]));
                update(a[i], 1), update(a[j], 1);
            }
        }
        printf("%lld
", ans);
    }
    return 0;
}