此题的二分输出一定是right才是对的（left， mid都wa）。。。以前遇到过一定要left才是ac的情况，请问大大这是为什么呢？
#include <iostream>
#include <algorithm>
using namespace std;

const int N=100005;
int arr[N];
int n, c;

bool jdg(int x)
{
	int num=arr[0];
	int i, j;
	j = 0;
	for (i=1; i<c; i++)
	{
		num += x;
		bool flag = false;
		for (j++; j<n; j++)
			if (num <= arr[j])
			{
				num = arr[j];
				flag = true;
				break;
			}
		if (flag == false)
			return 0;
	}
	return 1;
}

int main()
{
	//freopen ("in.txt", "r", stdin);
	int i;
	while (scanf("%d%d", &n, &c) ==2)
	{
		for (i=0; i<n; i++)
			scanf ("%d", &arr[i]);
		sort (arr, arr+n);
		int left, right, mid;
		right = (arr[n-1]-arr[0])/(c-1);
		left = 0;
		while (left <= right)
		{
			mid = (left + right)/2;
			if (jdg(mid))
				left = mid+1;
			else
				right = mid-1;
		}
		printf("%d\n", right);
	}
	return 0;
}

• Re:这题一定要用right才能ac...二分的输出应该怎么确定啊？ (184) The_Dawn 2011-07-12 20:08:56
• 我也不确定了，我是left ac的。。。一般都是left吧。。。 (0) lijingwei 2011-08-16 22:26:47