动态规划求解：第一行包含两个数R 和C （ 2 ≤ R,C ≤ 1500 ）为矩形地块的长和宽。接下来有R 行，每行有C 个用空格隔开的字符串，字符串要么以A 开头（表示

苹果），要么以B 开头（表示香蕉），后面接一个不超过99 的整数，表示对应的树木的数量。-Dynamic Programming: The first line contains two numbers R and C (2 ≤ R, C ≤ 1500) for the rectangular block of length and width. Then there are R lines, each with C a string separated by spaces, or to A at the beginning of the string (for Apple), or to B at the beginning (for banana), followed by an integer of not more than 99, indicating the corresponding number of trees.