题目链接：hdu 1166 敌兵布阵
题目大意：略。
解题思路：树状数组的水题。这篇题解很好，适合初学树状数组的人。题解连接
#include#include const int N = 50005; const int M = 105; int n, v[N]; void add(int x, int val) { while (x <= n) { v[x] += val; x += (x & (-x)); } } void init() { memset(v, 0, sizeof(v)); int a; scanf("%d", &n); for (int i = 1; i <= n; i++) { scanf("%d", &a); add(i, a); } } int sum(int x) { int ans = 0; while (x > 0) { ans += v[x]; x -= (x & (-x)); } return ans; } void solve() { int x, y; char order[M]; while (scanf("%s", order) == 1 && strcmp(order, "End") ) { scanf("%d%d", &x, &y); if (order[0] == 'A') add(x, y); else if (order[0] == 'S') add(x, -y); else printf("%d\n", sum(y) - sum(x-1)); } } int main() { int cas; scanf("%d", &cas); for (int i = 1; i <= cas; i++) { printf("Case %d:\n", i); init(); solve(); } return 0; }