在实际应用中，常遇到与区间有关的操作，比如统计若干矩形并集的面积，记录一个区间的最大最小值及总量，并在区间的插入、删除和修改中维护这些数据。线段树的定义是利用树形二分结构所建立的一种数据结构，能够高效的完成这些操作。-In practical applications, often encountered in the interval-related operations, such as statistics and set a number of rectangular area, recording minimum and maximum amount of a range, and the range of insert, delete, and modify the maintenance of these data. Defined segment tree is a tree data structure using a bipartite structure established, these operations can be completed efficiently.