hdu1166: http://acm.hdu.edu.cn/showproblem.php?pid=1166
题意:给出k个正整数,第i个正整数ai代表第i个工兵营地里开始时有ai个人,接下来有一些命令(增加、减少、查询、结束),输出每次查询结果。
解法:线段树
code:
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
const int inf=1<<29;
struct node
{
int left,right,n;
}v[1500000];
int l,r;
char b[10];
void build(int s,int t,int num) //建空树,初始化n为0
{
v[num].left=s;
v[num].right=t;
v[num].n=0;
if(s==t)return;
int mid=(s+t)/2;
build(s,mid,2*num);
build(mid+1,t,2*num+1);
}
void insert(int rr,int c,int num) //右端点,插入数目,区间编号
{
int mid=(v[num].left+v[num].right)/2;
if(v[num].left==v[num].right)
{
v[num].n+=c;
return;
}
if(rr<=mid)
{
v[num].n+=c;
insert(rr,c,2*num);
}
else if(rr>mid)
{
v[num].n+=c;
insert(rr,c,2*num+1);
}
}
int sum(int s,int t,int num) //查询
{
if(v[num].left==s&&v[num].right==t)
return v[num].n;
int mid=(v[num].left+v[num].right)/2;
if(t<=mid)
return sum(s,t,num*2);
else if(s>mid)
return sum(s,t,num*2+1);
else
return sum(s,mid,num*2)+sum(mid+1,t,num*2+1);
}
int main()
{
int cas,k,kk;
scanf("%d",&cas);
for(int j=1;j<=cas;j++)
{
scanf("%d",&k);
build(1,k,1);
for(int i=1;i<=k;i++)
{
scanf("%d",&kk);
insert(i,kk,1);
}
printf("Case %d:\n",j);
while(1)
{
scanf("%s",&b);
if(strcmp(b,"End")==0)
break;
scanf("%d%d",&l,&r);
if(strcmp(b,"Add")==0)
insert(l,r,1);
else if(strcmp(b,"Sub")==0)
insert(l,-r,1);
else
printf("%d\n",sum(l,r,1));
}
}
}
/*input:
1
10
1 2 3 4 5 6 7 8 9 10
Query 1 3
Add 3 6
Query 2 7
Sub 10 2
Add 6 3
Query 3 10
End
output:
Case 1:
6
33
59*/