Wood Cut

Description

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.

Link

Lintcode_ladder

Method

1. x
2. x

Example

1. 1

class Solution {
public:
    /** 
     *@param L: Given n pieces of wood with length L[i]
     *@param k: An integer
     *return: The maximum length of the small pieces.
     */
    int woodCut(vector<int> nums, int k) {
        // write your code here
        if (nums.empty()) {
            return 0;
        }
        int result = 0;
        int max_length = 0;
        // find max length we can cut
        for (int i = 0; i < nums.size(); ++i) {
           max_length = max(max_length, nums[i]);
        }
        // search result
        int start = 1;
        int end = max_length;
        while (start + 1 < end) {
            int mid = start + (end - start) / 2;
            // 
            int curcut = cutCounter(nums, mid);
            if (curcut >= k) {
                start = mid;
            } else {
                end = mid;
            }
        }
        // we can cut more than k times, not the less
        if (cutCounter(nums, end) >= k) {
            return end;
        } else if (cutCounter(nums, start) >= k) {
            return start;
        }
        return 0;
    }
private:
    int cutCounter(vector<int>& nums, int val) {
        if (val <= 0) {
            return 0;
        }
        int result = 0;
        for (int i = 0; i < nums.size(); ++i) {
            result += (nums[i]/val);
        }
        return result;
    }
};

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