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;

 1 public class Solution {
 2     /** 
 3      *@param L: Given n pieces of wood with length L[i]
 4      *@param k: An integer
 5      *return: The maximum length of the small pieces.
 6      */
 7     public int woodCut(int[] L, int k) {
 8         if (L == null || L.length == 0) return 0;
 9         int startLength = 1;
10         int endLength = maxLength(L);
11         
12         while (startLength <= endLength) {
13             int mid = startLength + (endLength - startLength) / 2;
14             if (count(L, mid) >= k) {
15                 startLength = mid + 1;
16             } else {
17                 endLength = mid - 1;
18             }
19         }
20         return startLength - 1; // using startLength will make count(L, startLength) < k
21     }
22     
23     public int count(int[] L, int length) {
24         int total = 0;
25         for (int i = 0; i < L.length; i++) {
26             total += L[i] / length;
27         }
28         return total;
29     }
30     
31     public int maxLength(int[] L) {
32         int max = L[0];
33         for (int i = 0; i < L.length; i++) {
34             max = Math.max(L[i], max);
35         }
36         return max;
37     }
38 }