hdu-1166敌兵布阵（树状数组）

此处的树状数组讲解请点击：here~~~

#include<stdio.h>
#include<string.h>
int n,a[50005],q[40005];
int lowbit(int x)
{
return x&(-x);
}
int Getsum(int pos)
{
int res = 0;
while(pos > 0)
{
res += a[pos];
pos -= lowbit(pos);
}
return res;
}
void add(int pos,int num)
{
while(pos <= n)
{
a[pos] += num;
pos += lowbit(pos);
}
}
int main()
{
int t,x,y,p=1;
char s[20];
scanf("%d",&t);
while(t--)
{
scanf("%d",&n);
memset(a,0,sizeof(a));
for(int i = 1;i <= n;i++)
{
scanf("%d",&x);
add(i,x);
}
int num = 0;
while(scanf("%s",s),strcmp(s,"End")!=0)
{
scanf("%d%d",&x,&y);
if(strcmp(s,"Query")==0)
q[num++] = Getsum(y) - Getsum(x-1);
else if(strcmp(s,"Add")==0)
add(x,y);
else
add(x,-y);
}
printf("Case %d:\n",p++);
for(int i = 0;i < num;i++)
{
printf("%d\n",q[i]);
}
}
}