賽前寫掛板子錯誤整理

P3378 【模板】堆

封裝版：

#include<cstdio>
#define rg register
#define ci const int
#define cl const long long int

typedef long long int ll;

namespace IO {
    char buf[300];
}

template <typename T>
inline void qr(T &x) {
    rg char ch=getchar(),lst=' ';
    while((ch > '9') || (ch < '0')) lst=ch,ch=getchar();
    while((ch >= '0') && (ch <= '9')) x=(x<<1)+(x<<3)+(ch^48),ch=getchar();
    if(lst == '-') x=-x;
}

template <typename T>
inline void qw(T x,const char aft,const bool pt) {
    if(x < 0) {putchar('-');x=-x;}
    rg int top=0;
    do {
        IO::buf[++top]=x%10+'0';
    } while(x/=10);
    while(top) putchar(IO::buf[top--]);
    if(pt) putchar(aft);
}

template <typename T>
inline T mmax(const T a,const T b) {return a > b ? a : b;}
template <typename T>
inline T mmin(const T a,const T b) {return a < b ? a : b;}
template <typename T>
inline T mabs(const T a) {return a < 0 ? -a : a;}

template <typename T>
inline void mswap(T &a,T &b) {
    T _temp=a;a=b;b=_temp;
}

const int maxn = 1000010;

template <typename T>
struct Heap{
    T heap[maxn];
    int hcnt;
    inline bool empty() {return !hcnt;}
    inline int sz() {return hcnt;}
    void push(const T &x) {
        int pos;
        heap[pos=++hcnt]=x;
        while(pos != 1) {
            int fa = pos>>1;
            if(heap[pos] < heap[fa]) mswap(heap[fa],heap[pos]);
            pos>>=1;
        }
    }
    void pop() {
        int pos;
        heap[pos=1]=heap[hcnt--];
        while((pos<<1) <= hcnt) {
            int s=pos<<1;
            if((s < hcnt) && (heap[s|1] < heap[s])) s|=1;
            if(heap[pos] > heap[s]) mswap(heap[pos],heap[s]);
            pos=s;
        }
    }
    inline T top() {
        return heap[1];
    }
};
Heap<int>Q;

int n;

int main() {
    qr(n);
    int a;
    while(n--) {
        a=0;qr(a);
        if(a == 1) {
            a=0;qr(a);Q.push(a);
        } else if(a == 2) {
            qw(Q.top(),'\n',true);
        } else {
            Q.pop();
        }
    }
    return 0;
}
 

未封裝：

#include<cstdio>
#define rg register
#define ci const int
#define cl const long long int

typedef long long int ll;

namespace IO {
    char buf[300];
}

template <typename T>
inline void qr(T &x) {
    rg char ch=getchar(),lst=' ';
    while((ch > '9') || (ch < '0')) lst=ch,ch=getchar();
    while((ch >= '0') && (ch <= '9')) x=(x<<1)+(x<<3)+(ch^48),ch=getchar();
    if(lst == '-') x=-x;
}

template <typename T>
inline void qw(T x,const char aft,const bool pt) {
    if(x < 0) {putchar('-');x=-x;}
    rg int top=0;
    do {
        IO::buf[++top]=x%10+'0';
    } while(x/=10);
    while(top) putchar(IO::buf[top--]);
    if(pt) putchar(aft);
}

template <typename T>
inline T mmax(const T a,const T b) {return a > b ? a : b;}
template <typename T>
inline T mmin(const T a,const T b) {return a < b ? a : b;}
template <typename T>
inline T mabs(const T a) {return a < 0 ? -a : a;}

template <typename T>
inline void mswap(T &a,T &b) {
    T _temp=a;a=b;b=_temp;
}

const int maxn = 1000010;

int n,hcnt;
int heap[maxn];

void add(ci);
int ask();
void dlt();

int main() {
    qr(n);
    int a;
    while(n--) {
        a=0;qr(a);
        if(a == 1) {
            a=0;qr(a);add(a);
        } else if(a == 2) {
            qw(ask(),'\n',true);
        } else {
            dlt();
        }
    }
    return 0;
}

void add(ci x) {
    int pos;
    heap[pos=++hcnt]=x;
    while(pos != 1) {
        int fa=pos>>1;
        if(heap[fa] > heap[pos]) mswap(heap[pos],heap[fa]);
        pos>>=1;
    }
}

inline int ask() {return heap[1];}

void dlt() {
    int pos;
    heap[pos=1]=heap[hcnt--];
    while((pos << 1) <= hcnt) {
        int s=pos<<1;
        if((s < hcnt) && (heap[s|1] < heap[s])) s|=1;
        if(heap[s] < heap[pos]) mswap(heap[pos],heap[s]);
        pos=s;
    }
}
 

錯誤一：

刪除函式中

while((pos<<1) <= hcnt) 

小於等於寫成小於

錯誤二：

刪除函式中

pos=s;

寫成pos<<=1。（因為可能pos=pos<<1|1)

錯誤三：

刪除函式中

while((pos<<1) <= hcnt) 

寫成pos<=hcnt