hdu1166 敌兵布阵 (树状数组)

#include <stdio.h>
#include <string.h>
#define MAX 1000005

int arr[MAX],n;
//树状数组
int lowBit(int x)//二进制后面为0的个数
{
return (x&(-x));
}

void add(int index,int val)//将index位置的值+val
{
while(index<=n)
{
arr[index]+=val;
index+=lowBit(index);
}
}

int func(int num)
{
int sum=0;
while(num>0)
{
sum+=arr[num];
num-=lowBit(num);//找到num前的所有最大子树
}
return sum;
}
int main()
{
int test,i,s,t,ai,cases=1;
char cmd[10];
scanf("%d",&test);
while(test--)
{
memset(arr,0,sizeof(arr));
printf("Case %d:\n",cases++);
scanf("%d",&n);
for(i=1;i<=n;i++)
{
scanf("%d",&ai);
add(i,ai);
}
while(scanf("%s",cmd))
{
if(cmd[0]=='E')
break;
scanf("%d %d",&s,&t);
if(cmd[0]=='A')
add(s,t);
else if(cmd[0]=='S')
add(s,-t);
else
printf("%d\n",func(t)-func(s-1));
}
}
return 0;
}

//线段树
#include <stdio.h>

int sum[200002];

void pushUP(int root)
{
sum[root]=sum[root<<1]+sum[root<<1|1];
}

void build(int left,int right,int root)
{
int mid;
if(left==right)
{
scanf("%d",&sum[root]);
return;
}
mid=(left+right)>>1;
build(left,mid,root<<1);
build(mid+1,right,root<<1|1);
pushUP(root);
}

void updata(int p,int add,int left,int right,int root)
{
int mid;
if(left==right)
{
sum[root]+=add;
return;
}
mid=(left+right)>>1;
if(p<=mid)
updata(p,add,left,mid,root<<1);
else
updata(p,add,mid+1,right,root<<1|1);
pushUP(root);
}

int query(int st,int end,int left,int right,int root)
{
int mid,ans=0;
if(st<=left&&end>=right)
return sum[root];
mid=(left+right)>>1;
if(st<=mid)
ans+=query(st,end,left,mid,root<<1);
if(end>mid)
ans+=query(st,end,mid+1,right,root<<1|1);
return ans;
}

int main()
{
int test,n,x,y,i;
char cmd[10];
scanf("%d",&test);
for (i=1;i<=test;i++)
{
printf("Case %d:\n",i);
scanf("%d",&n);
build(1,n,1);
while(scanf("%s",cmd)&&cmd[0]!='E')
{
scanf("%d %d",&x,&y);
if(cmd[0]=='Q')
printf("%d\n",query(x,y,1,n,1));
else if(cmd[0]=='S')
updata(x,-y,1,n,1);
else
updata(x,y,1,n,1);
}
}
return 0;
}