Wood Cut

Problem:

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.

If you couldn't get >= k pieces, return 0.

Analysis:
Binary search, guess the result. If guess value (cut by assumed wood length) >= k, then increase the guess value.

Solution:
Start always satisfy the requirement, so just return start.

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) {
        // write your code here
        if (L == null || L.length == 0) return 0;
        int start= 0, end= Integer.MAX_VALUE;  
        while (start+ 1< end) {  
            int mid = start+ (end- start)/2;  
            int temp = helper(L, mid);
            if (temp >= k){  
                start = mid;
            }  else {
                end= mid;
            }
         }
        return start;

    }

    private int helper(int[] L, int len) {
        int res = 0;
        for (int i = 0 ; i < L.length; i++) {
            res += L[i] / len;
        }
        return res;
    }
}