Wood Cut

LintCode-183.Wood Cut

Given n pieces of wood with length L[i] (integer array). Cut them into small pieces to guarantee you could have equal or more than k pieces with the same length. What is the longest length you can get from the n pieces of wood? Given L & k, return the maximum length of the small pieces.

Notice

You couldn't cut wood into float length.

Example

For L=[232, 124, 456], k=7, return 114.

Challenge

O(n log Len), where Len is the longest length of the wood.

public class Solution {  
    /** 
     *@param L: Given n pieces of wood with length L[i]
     *@param k: An integer
     *return: The maximum length of the small pieces.
     */
    public int woodCut(int[] L, int k) {
        if (L == null || L.length == 0 || k <= 0) {
            return 0;
        }

        Arrays.sort(L);
        int start = 1, end = L[L.length - 1];

        while (start <= end) {
            int middle = start + (end - start) / 2;

            if (getPieces(L, middle) >= k) {
                start = middle + 1;
            } else {
                end = middle - 1;
            }
        }

        return end;
    }

    int getPieces(int[] L, int len) {
        int count = 0;

        for (int i : L) {
            count += i / len;
        }

        return count;
    }
}

Hope this helps,
Michael