最近看的一个小算法

         最近想看算法书，一不小心看到的一个小东西，好久没更，更上来看 看。

#coding=utf-8       # 计算和最大的子数组  def divide_a(low, high):     return (low + high) / 2  def combine_a(left_sub, right_sub, cross_sub):     if left_sub[2] > right_sub[2] and left_sub[2] > cross_sub[2]:         return left_sub     elif right_sub[2] > left_sub[2] and right_sub[2] > cross_sub[2]:         return right_sub     else:         return cross_sub  def find_max_cross(A, low, high, mid):     left_sum = 0     left_max_sum =A[mid]     left_max_low = mid     for i in range(mid, low-1, -1):         left_sum = A[i] + left_sum         if left_max_sum < left_sum :             left_max_low = i             left_max_sum = left_sum     right_sum = 0     right_max_sum = A[mid + 1]     right_max_high = mid + 1      for i in range(mid + 1, high+1):         right_sum = A[i] + right_sum         if right_max_sum < right_sum:              right_max_high = i;             right_max_sum = right_sum;     print (left_max_low, right_max_high, left_max_sum + right_max_sum)     return (left_max_low, right_max_high, left_max_sum + right_max_sum)  def divide_and_conquer_a(A, low, high):         #攻克     if low == high:         return (low, high, A[low])         #分解     mid = divide_a(low, high)         #递归     left_sub = divide_and_conquer_a(A, low, mid)     right_sub = divide_and_conquer_a(A, mid+1, high)     cross_sub = find_max_cross(A, low, high, mid)         #合并     return combine_a(left_sub, right_sub, cross_sub)  if __name__ == "__main__":     A = [13, -3, -25, 20, -3, -16, -23, 18, 20, -7, 12, -5, -22, 15, -4, 7]     t = divide_and_conquer_a(A,0,15)     print t