LeetCode第4题：寻找两个有序数组的中位数

 

double Solution::findMedianSortedArrays(vector<int>& nums1, vector<int>& nums2)
{
    if (nums1.size() > nums2.size())
    {
        return findMedianSortedArrays(nums2, nums1);
    }

    int m = nums1.size();
    int n = nums2.size();    //m <= n

    int left = 0, right = m, ansi=-1;
    int midNum1 = 0, midNum2 = 0;
    auto max = [](int a, int b)
    {
        return a >= b ? a : b;
    };
    auto min = [](int a, int b)
    {
        return a <= b ? a : b;
    };
    while (left <= right)
    {
        int i = (left + right) / 2;
        int j = (m + n + 1) / 2 - i;

        int i_1 = i == 0 ? INT_MIN : nums1[i - 1];
        int i_0 = i == m ? INT_MAX : nums1[i];

        int j_1 = j == 0 ? INT_MIN : nums2[j - 1];
        int j_0 = j == n ? INT_MAX : nums2[j];
        if (i_1 <= j_0)
        {
            ansi = i;
            midNum1 = max(i_1, j_1);
            midNum2 = min(i_0, j_0);
            left = i + 1;
        }
        else
        {
            right = i - 1;
        }
    }
    return (1 == (m + n) % 2) ? (double)midNum1 : (double)(midNum1 + midNum2) / 2;
}