priority_queue

P3378 【模板】堆

题目描述

题目链接

如题，初始小根堆为空，我们需要支持以下3种操作：
操作1： 1 x 表示将x插入到堆中
操作2： 2 输出该小根堆内的最小数
操作3： 3 删除该小根堆内的最小数

binary_heap

/*
584ms/468ms
*/

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

const int N = 1000010;

int n;
int key[N];

void Up(int k) {
    for (; k > 1 && key[k] < key[k / 2]; k /= 2)
        swap(key[k], key[k / 2]);
    return;
}

void Down(int k) {
    for (; k * 2 <= n; ) {
        int j = k * 2;
        if (j + 1 <= n && key[j] > key[j + 1]) ++j;
        if (key[k] > key[j]) {
            swap(key[k], key[j]);
            k = j;
        } else break;
    }
    return;
}

void Pop() {
    if (!n) throw;
    key[1] = key[n--];
    Down(1);
    return;
}

void Push(int x) {
    key[++n] = x;
    Up(n);
    return;
}

inline int Top() {
    return key[1];
}

int main() {
    int m;
    scanf("%d", &m);
    while (m--) {
        int t;
        scanf("%d", &t);
        if (t == 1) {
            int x;
            scanf("%d", &x);
            Push(x);
        } else if (t == 2) printf("%d\n", Top());
        else Pop();
    }
    return 0;
}

priority_queue

/*
1320ms/480ms
*/

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>

using namespace std;

priority_queue<int, vector<int>, greater<int> > pq;

int main() {
    int m;
    scanf("%d", &m);
    while (m--) {
        int t;
        scanf("%d", &t);
        if (t == 1) {
            int x;
            scanf("%d", &x);
            pq.push(x);
        } else if (t == 2) printf("%d\n", pq.top());
        else pq.pop();
    }
    return 0;
}

heap

/*
676ms/480ms
*/

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;

const int N = 1000010;

int n;
int key[N];

void Push(int x) {
    key[++n] = x;
    push_heap(key + 1, key + n + 1, greater<int>());
    return;
}

void Pop() {
    pop_heap(key + 1, key + n + 1, greater<int>());
    --n;
    return;
}

inline int Top() {
    return key[1];
}

int main() {
    int m;
    scanf("%d", &m);
    n = 0;
    // make_heap(key + 1, key + n + 1, greater<int>());
    while (m--) {
        int t;
        scanf("%d", &t);
        if (t == 1) {
            int x;
            scanf("%d", &x);
            Push(x);
        } else if (t == 2) printf("%d\n", Top());
        else Pop();
    }
    return 0;
}

pb_ds库

头文件

#include <ext/pb_ds/priority_queue.hpp>

命名空间

using namespace __gnu_pbds; 

定义

template < typename Value_Type ,
typename Cmp_Fn = std :: less < Value_Type > ,
typename Tag = pairing_heap_tag ,
typename Allocator = std :: allocator < char > >
class priority_queue

#include <iostream>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/priority_queue.hpp>

using namespace std;

__gnu_pbds::priority_queue<int, greater<int> > pq;
// __gnu_pbds::priority_queue<int, greater<int>, __gnu_pbds::pairing_heap_tag> pq;
// __gnu_pbds::priority_queue<int, greater<int>, __gnu_pbds::binomial_heap_tag> pq;
// __gnu_pbds::priority_queue<int, greater<int>, __gnu_pbds::rc_binomial_heap_tag> pq;
// __gnu_pbds::priority_queue<int, greater<int>, __gnu_pbds::binary_heap_tag> pq;

int main() {
    int m;
    scanf("%d", &m);
    while (m--) {
        int t;
        scanf("%d", &t);
        if (t == 1) {
            int x;
            scanf("%d", &x);
            pq.push(x);
        } else if (t == 2) printf("%d\n", pq.top());
        else pq.pop();
    }
    return 0;
}

与std::priority queue 的用法基本相同，有size()，empty()，push(const T)，top()，pop()，clear()。

配对堆（pairing_heap）、二叉堆（binary_heap）、二项堆（binomial_heap）、冗余计数二项堆（redundant-counter binomial_heap，没找到通用译名，故自行翻译）、经改良的斐波那契堆（thin_heap）。

懒，留坑

C++的pd_ds库在OI中的应用