codeforces962D

div2D

sol：

每次找到两个最小的数，如果相同则塞回去一个，不同则存下小的作为答案

复习一波优先队列

#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef int ll;
inline ll read()
{
    ll s=0; bool f=0; char ch=' ';
    while(!isdigit(ch)) {f|=(ch=='-'); ch=getchar();}
    while(isdigit(ch)) {s=(s<<3)+(s<<1)+(ch^48); ch=getchar();}
    return (f)?(-s):(s);
}
#define R(x) x=read()
inline void write(ll x)
{
    if(x<0) {putchar('-'); x=-x;}
    if(x<10) {putchar(x+'0'); return;}
    write(x/10); putchar((x%10)+'0');
}
#define W(x) write(x),putchar(' ')
#define Wl(x) write(x),putchar('\n')
const int N=200005;
int n,a[N];
struct node
{
    int v,id;
    bool operator<(const node &tmp) const
    {
        return (tmp.v==v)?tmp.id<id:tmp.v<v;
    }
}lwj[N];
priority_queue<node>que,wwx;
inline bool cmp(node pp,node qq)
{
    return pp.id<qq.id;
}
signed main()
{
//    freopen("codeforces.in","r",stdin);
    int i,cnt=0;
    R(n);
    for(i=1;i<=n;i++) R(a[i]);
    if(n==1)
    {
        Wl(1);
        Wl(a[1]);
        return 0;
    }
    for(i=1;i<=n;i++) que.push((node){a[i],i});
//    for(i=1;i<=n;i++)
//    {
//        node tmp=que.top();
//        cout<<tmp.id<<" "<<tmp.v<<endl;
//        que.pop();
//    }
    node wn,wq;
    while(que.size()>1)
    {
        wn=que.top();
        que.pop();
        wq=que.top();
        que.pop();
//        cout<<wn.v<<" "<<wn.id<<" "<<wq.v<<" "<<wq.id<<endl;
        if(wn.v^wq.v)
        {
            wwx.push(wn);
            que.push(wq);
        }
        else
        {
            que.push((node){wn.v*2,wq.id});
        }
    }
    wwx.push(que.top());
    Wl((int)wwx.size());
    while(wwx.size()>0)
    {
        lwj[++cnt]=wwx.top();
        wwx.pop();
    }
    sort(lwj+1,lwj+cnt+1,cmp);
    for(i=1;i<=cnt;i++) W(lwj[i].v);
    return 0;
}