【树状数组 + 简单题】杭电 hdu 1166 敌兵布阵

/* THE PROGRAM IS MADE BY PYY */ /*----------------------------------------------------------------------------// Copyright (c) 2011 panyanyany All rights reserved. URL : http://acm.hdu.edu.cn/showproblem.php?pid=1166 Name : 1166 敌兵布阵 Date : Sunday, September 18, 2011 Time Stage : half an hour Result: 4622505 2011-09-18 14:51:36 Accepted 1166 31MS 412K 1406 B C++ pyy小号 Test Data : Review : 第二次做，理解了树状数组的原理，其实是很简单的 //----------------------------------------------------------------------------*/ #define _CRT_SECURE_NO_WARNINGS #include <stdio.h> #include <string.h> #define MAXSIZE 50001 int tcase, n ; int tree[MAXSIZE] ; int lowbit (int x) { return (x) & (-x) ; } void add (int pos, int val) { while (pos <= n) { tree[pos] += val ; pos += lowbit (pos) ; } } int getSum (int x) { int sum = 0 ; while (x > 0) { sum += tree[x] ; x -= lowbit (x) ; } return sum ; } int main () { char str[20] ; int i, j ; int x, y ; while (scanf ("%d", &tcase) != EOF) { for (j = 1 ; j <= tcase ; ++j) { memset (tree, 0, sizeof (tree)) ; scanf ("%d", &n) ; for (i = 1 ; i <= n ; ++i) { scanf ("%d", &x) ; add (i, x) ; } printf ("Case %d:\n", j) ; while (scanf ("%s", str), *str != 'E') { scanf ("%d%d", &x, &y) ; if (*str == 'Q') printf ("%d\n", getSum (y) - getSum (x - 1)) ; else if (*str == 'A') add (x, y) ; else if (*str == 'S') add (x, -y) ; } } } return 0 ; }