篱笆修理(Fence Repair) 代码(C)

本文地址: http://blog.csdn.net/caroline_wendy

题目: 把一块木板切成N块, 每次切两块, 切割的开销是木板长度, 求将木板切割完的最小开销.

即霍夫曼编码(Huffman).

贪心算法, 类似二叉树型结构, 最短板和次短板是兄弟结点, 选取两个最小木板, 最后进行切割, 合并两个最小木板, 依次递推.

代码:

/*
 * main.cpp
 *
 *  Created on: 2014.7.17
 *      Author: spike
 */

/*eclipse cdt, gcc 4.8.1*/

#include <stdio.h>
#include <limits.h>

#include <utility>
#include <queue>
#include <algorithm>

using namespace std;

class Program {
	typedef long long ll;
	static const int MAX_N = 10000;

	int N=5, L[MAX_N]={1,2,3,4,5};

public:
	void solve() {
		ll ans = 0;
		while (N>1) {
			int mii1 = 0, mii2 = 1;
			if (L[mii1]>L[mii2]) swap(mii1, mii2);
			for (int i=2; i<N; ++i) {
				if (L[i]<L[mii1]) {
					mii2 = mii1;
					mii1 = i;
				} else if (L[i]<L[mii2]) {
					mii2 = i;
				}
			}
			int t = L[mii1]+L[mii2];
			ans += t;
			if (mii1 == N-1) swap(mii1, mii2);
			L[mii1] = t;
			L[mii2] = L[N-1];
			N--;
		}
		printf("result = %lld\n", ans);
	}
};


int main(void)
{
	Program P;
	P.solve();
    return 0;
}

result = 33