ZOJ 3279 Ants(線段樹)
阿新 • • 發佈:2019-02-16
echo is a curious and clever girl, and she is addicted to the ants recently.
She knows that the ants are divided into many levels depends on ability, also, she finds the number of each level will change.
Now, she will give two kinds of operations as follow :
First, "p a b", the number of ants in level a change to b.
Second, "q x", it means if the ant's ability is rank xth in all ants, what level will it in?
Input
There are multi-cases, and you should use EOF to check whether it is in the end of the input. The first line is an integer n, means the number of level. (1 <= n
Output
Output each query in order, one query each line.
Sample Input
3 1 2 3 3 q 2 p 1 2 q 2
Sample Output
2 1Author: Lin, Yue
Source: ZOJ Monthly, December 2009
給出每個等級的數目,後面m個操作,q查詢排名x在第幾個等級,p a b,把a等級的數目改為b
ac程式碼
#include<stdio.h>
#include<string.h>
int node[100010<<2];
void build(int l,int r,int tr)
{
if(l==r)
{
scanf("%d",&node[tr]);
return;
}
int mid=(l+r)>>1;
build(l,mid,tr<<1);
build(mid+1,r,tr<<1|1);
node[tr]=node[tr<<1]+node[tr<<1|1];
}
void update(int pos,int val,int l,int r,int tr)
{
if(l==r)
{
node[tr]=val;
return;
}
int mid=(l+r)>>1;
if(pos<=mid)
update(pos,val,l,mid,tr<<1);
else
update(pos,val,mid+1,r,tr<<1|1);
node[tr]=node[tr<<1]+node[tr<<1|1];
}
int query(int val,int l,int r,int tr)
{
if(l==r)
{
return l;
}
int mid=(l+r)>>1;
if(val<=node[tr<<1])
query(val,l,mid,tr<<1);
else
query(val-node[tr<<1],mid+1,r,tr<<1|1);
}
int main()
{
int n;
while(scanf("%d",&n)!=EOF)
{
int i;
memset(node,0,sizeof(node));
build(1,n,1);
int m;
scanf("%d",&m);
while(m--)
{
char s[2];
scanf("%s",s);
if(s[0]=='q')
{
int x;
scanf("%d",&x);
int ans=query(x,1,n,1);
printf("%d\n",ans);
}
else
{
int a,b;
scanf("%d%d",&a,&b);
update(a,b,1,n,1);
}
}
}
}