【leetcode】子数组最大平均数 I

double findMaxAverage(int* nums, int numsSize, int k){
    double max=0,sum;
    int i;
    for (i=0; i<k; i++)
        max += nums[i];
    sum = max;
    for (i=k; i<numsSize; i++)
    {
        sum += nums[i] - nums[i-k];
        if (sum > max) max = sum;        
    }    
    return max/k;
}