Educational Codeforces Round 42 (Rated for Div. 2) D. Merge Equals

题目链接

D. Merge Equals

time limit per test

2 seconds

memory limit per test

256 megabytes

You are given an array of positive integers. While there are at least two equal elements, we will perform the following operation. We choose the smallest value $\mathrm{xx that\; occurs\; in\; the\; array 22 or\; more\; times.\; Take\; the\; first\; two\; occurrences\; of xx in\; this\; array\; (the\; two\; leftmost\; occurrences).\; Remove\; the\; left\; of\; these\; two\; occurrences,\; and\; the\; right\; one\; is\; replaced\; by\; the\; sum\; of\; this\; two\; values\; (that\; is, 2\cdot x2\cdot x).}$

Determine how the array will look after described operations are performed.

For example, consider the given array looks like $[3,4,1,2,2,1,1][3,4,1,2,2,1,1].\; It\; will\; be\; changed\; in\; the\; following\; way: [3,4,1,2,2,1,1] \to [3,4,2,2,2,1] \to [3,4,4,2,1] \to [3,8,2,1][3,4,1,2,2,1,1] \to [3,4,2,2,2,1] \to [3,4,4,2,1] \to [3,8,2,1].$

If the given array is look like $[1,1,3,1,1][1,1,3,1,1] it\; will\; be\; changed\; in\; the\; following\; way: [1,1,3,1,1] \to [2,3,1,1] \to [2,3,2] \to [3,4][1,1,3,1,1] \to [2,3,1,1] \to [2,3,2] \to [3,4].$

Input

The first line contains a single integer $\mathrm{nn (2\le n\le 1500002\le n\le 150000)\; —\; the\; number\; of\; elements\; in\; the\; array.}$

The second line contains a sequence from $\mathrm{nn elements a1,a2,\dots ,ana1,a2,\dots ,an (1\le ai\le 1091\le ai\le 109)\; —\; the\; elements\; of\; the\; array.}$

Output

In the first line print an integer $\mathrm{kk —\; the\; number\; of\; elements\; in\; the\; array\; after\; all\; the\; performed\; operations.\; In\; the\; second\; line\; print kk integers\; —\; the\; elements\; of\; the\; array\; after\; all\; the\; performed\; operations.}$

Examples

input

7
3 4 1 2 2 1 1

output

4
3 8 2 1 

input

5
1 1 3 1 1

output

2
3 4 

input

5
10 40 20 50 30

output

5
10 40 20 50 30 

Note

The first two examples were considered in the statement.

In the third example all integers in the given array are distinct, so it will not change.

AC代码：

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn=3e5+10;
map<ll,int>mp1,mp2;
ll ans[maxn],n,x,cnt;
int main()
{
    int n;
    cin>>n;
    for(int i=0; i<n; i++)
    {
        cin>>x;
        if(mp1[x]==0)
        {
            mp1[x]++;
            mp2[x]=i;
            ans[i]=x;
        }
        else
        {
            while(mp1[x]!=0)
            {
                mp1[x]--;
                ans[mp2[x]]=-1;
                x*=2;
                ans[i]=x;
            }
            mp1[x]++;
            mp2[x]=i;
        }
    }
    for(int i=0; i<n; i++)
        if(ans[i]!=-1)
            cnt++;
    cout<<cnt<<endl;
    for(int i=0; i<n; i++)
        if(ans[i]!=-1)
            cout<<ans[i]<<' ';
    cout<<endl;

    return 0;
}