摘要： http://acm.hdu.edu.cn/showproblem.php?pid=1394 线段树求逆序数，先求出初始数组的逆序数(n logn)，然后o(1)推出其他逆序数。因为输入为0--n-1，所以建树从0开始。code:#include<cstdlib>#include<cctype>#include<cstring>#include<cstdio>#include<cmath>#include<algorithm>#include<vector>#include<string>#incl 阅读全文