C++-HDU1166-敌兵布阵[数据结构][树状数组]

单点修改+区间查询=树状数组

空间复杂度O(n)

时间复杂度O(mlogn)

 #include <set>
 #include <map>
 #include <cmath>
 #include <queue>
 #include <vector>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <iostream>
 #include <algorithm>
 using namespace std;
 const int MAXN=;
 int a[MAXN],n,t=,T;char s[];
 int lb(int i){return i&-i;}//lowbit
 void init(){memset(a,,sizeof(a));}
 void add(int i,int v){for(;i<=n;a[i]+=v,i+=lb(i));}
 int sum(int i){int ans=;for(;i;ans+=a[i],i-=lb(i));return ans;}
 int query(int i,int j){return sum(j)-sum(i-);}
 int main() {
     for(scanf("%d",&T);t<=T;t++){
         scanf("%d",&n),init();
         for(int i=,v;i<=n;i++)scanf("%d",&v),add(i,v);
         printf("Case %d:\n",t);
         for(int x,y;scanf("%s",s)&&s[]!='E';){
             scanf("%d%d",&x,&y);
             if(s[]=='A')add(x,y);
             else if(s[]=='S')add(x,-y);
             else printf("%d\n",query(x,y));
         }
     }
     return ;
 }