HDU 1551（Cable master）

基礎題，二分查找即可。

#include <iostream>
#include <iomanip>
using namespace std;
const int MAXN = 10005;
const double eps = 1e-6;

double len[MAXN]; //每段繩子的長度
int N, K;

//判斷是否能得到K段長爲x的繩子
bool check(double x) 
{
	int total = 0;
	for (int i = 0; i < N; i++)
		total += (int)(len[i] / x);

	if (total >= K) 
		return true;
	else
		return false;
}

int main() 
{
	while (cin >> N >> K) 
	{
		if (N == 0 && K == 0)
			break;

		for (int i = 0; i < N; i++)
		{
			cin >> len[i];
		}

		double l = 0, r = 100000, mid;
		while (r - l > eps) //二分查找
		{
			mid = (r + l) / 2;
			if (check(mid))
				l = mid;		
			else
				r = mid;
		}
		cout << fixed << setprecision(2) << l << endl;
	}
	return 0;
}

繼續加油。