topcoder SRM 622 DIV2 BoxesDiv2

注意题目这句话，Once you have each type of candies in a box, you want to pack those boxes into larger boxes, until only one box remains.

两个box合并后必须放入更大一个盒子

题目的有点类似huffman的前部分，此题用堆去做，由于priority_queue是用堆实现的，故可以直接使用

每次从堆中选取最小的两个进行合并即可

#include <iostream>
#include <queue>
#include <vector>
#include <algorithm>
using namespace std;

class BoxesDiv2{
public:
    int round_up(int x){
        for(int i = 0; i <=10 ; ++ i){
            if( 1<<i >= x ) return 1<<i;
        }
        return 1<<11;
    }
    
    int findSize(vector<int> candyCounts){
        priority_queue<int,vector<int>,greater<int> > boxQueue;
        for(int i = 0 ; i < candyCounts.size(); ++ i){
            boxQueue.push(round_up(candyCounts[i]));
        }
        while(boxQueue.size() != 1){
            int a = boxQueue.top();boxQueue.pop();
            int b = boxQueue.top();boxQueue.pop();
            boxQueue.push(max(a,b)*2);
        }
        return boxQueue.top();
    }
};