装箱问题（中兴笔试）

 给定有n个物体，用数组表示各个物体的大小，箱子容量为capacity,最少用多少个箱子把这n个物体装下

方法1：

 #include <iostream>

using namespace std;

int minContainer(int len, int capacity, int arr[]) {
	struct BNode
	{
		int remain;
		BNode* next;
	};
	BNode* pHead = nullptr;
	BNode* pNode = nullptr;
	BNode* pTail = nullptr;
	for (int i = 0; i < len; ++i) {
		pNode = pHead; //每次从头开始
		while (pNode ！= nullptr && pNode->remain < arr[i])
			pNode = pNode->next;

		if (pNode == nullptr) {
			//需要开新箱子
			pNode = new BNode();
			pNode->remain = capacity;
			pNode->next = nullptr;

			if (!pHead) {
				//头节点为空，设置头节点
				pHead = pTail = pNode;
			}
			else{
				pTail->next = pNode; //旧箱子的最后一个箱子指向新箱子
				pTail = pNode; //更新pTail指向最后一个箱子	
			}
		}
		
		pNode->remain -= arr[i];
	}

	//统计箱子数
	int boxNum = 0;
	pNode = pHead;
	while (pNode != nullptr) {
		boxNum++;
		pNode = pNode->next;
	}

	return boxNum;
}

int main() {
	//int arr[5] = { 4, 8, 6, 7, 8 }; //boxNum = 4
	int arr[9] = { 6, 5, 2, 1, 7, 4, 9, 10 }; //boxNum = 5
	sort(arr, arr + 9,
		[] (int a, int b)
		{return a > b;}); //降序排列
	cout << minContainer(9, 12, arr) << endl;
	system("pause");
}

方法2：

#include <iostream>
#include <list>

using namespace std;

int minContainer(int len, int capacity, int arr[]) {
	list<int> ilst;
	//ilst.push_back(capacity);
	list<int>::iterator lst_it; //= ilst.begin();

	for(int i = 0; i < len; ++i){
		lst_it = ilst.begin(); //每次从头开始
		while(*lst_it < arr[i])//查找刚好能放下arr[i]的箱子
			++lst_it;
		
                 //当前箱子都放不下arr[i]
		if(lst_it == ilst.end()){
                  
			ilst.push_back(capacity);
			--lst_it;//lst_it指向新加入的箱子
		}

		*lst_it -= arr[i];
	}


	return ilst.size();
}
bool compare(int a, int b)
{return a > b;}

int main() {
	//int arr[5] = { 4, 8, 6, 7, 8 }; //boxNum = 4
	int arr[9] = { 6, 5, 2, 1, 7, 4, 9, 10, 4}; //boxNum = 5
        //int arr[7] = {2, 5, 4, 7, 1, 3, 8};//boxNum = 3
	sort(arr, arr + 9, compare); //降序排列
	cout << minContainer(9, 12, arr) << endl;
	system("pause");
}