[容易]中位数

题目来源：http://www.lintcode.com/zh-cn/problem/median/

C++版 VS2012测试通过

方法一

class Solution {
public:
    /**
     * @param nums: A list of integers.
     * @return: An integer denotes the middle number of the array.
     */
    int median(vector<int> &nums) {
        // write your code here
        sort(nums.begin(),nums.end());
        if(nums.size()%2==0)
            return nums.at(nums.size()/2-1);
        else
            return nums.at((nums.size()-1)/2);
    }
};

方法二

class Solution {
public:
    /**
     * @param nums: A list of integers.
     * @return: An integer denotes the middle number of the array.
     */
    int median(vector<int> &nums) {
        // write your code here
        int k = (nums.size() + 1) / 2;
        priority_queue<int> que;
        int len = nums.size();
        for(int i = 0; i < len; i ++) {
            if(que.size() == k) {
                if(nums[i] < que.top()) {
                    que.pop();
                    que.push(nums[i]);
                }
            }else {
                que.push(nums[i]);
            }
        }
        return que.top();
    }
};

Python2.7版 spider测试通过

class Solution:
    """
    @param nums: A list of integers.
    @return: An integer denotes the middle number of the array.
    """
    def median(self, nums):
        # write your code here
        nums.sort()
        return nums[(len(nums)-1)/2]

#测试
#if __name__=='__main__':
#    n=[4,5,7,9]
#    s=Solution()
#    print s.median(n)