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.

You couldn't cut wood into float length.

Example

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

Analysis:

From 1 to Max(L), use binary search to find the maximum length;

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) return 0;
        int startLength = 1;
        int endLength = maxLength(L);
        
        while (startLength <= endLength) {
            int mid = startLength + (endLength - startLength) / 2;
            if (count(L, mid) >= k) {
                startLength = mid + 1;
            } else {
                endLength = mid - 1;
            }
        }
        return startLength - 1; // using startLength will make count(L, startLength) < k
    }
    
    public int count(int[] L, int length) {
        int total = 0;
        for (int i = 0; i < L.length; i++) {
            total += L[i] / length;
        }
        return total;
    }
    
    public int maxLength(int[] L) {
        int max = L[0];
        for (int i = 0; i < L.length; i++) {
            max = Math.max(L[i], max);
        }
        return max;
    }
}