线段树与主席树详解-优快云博客

2021.8.16修改直接把两大神树都搬过来吧

线段树

#include<iostream>
#include<cmath>
using namespace std;
const int N=2e5+10;
long long a[N],sub[N];
long long lz[N];
int n;
long long tree[N<<2];
 
inline long long query(int l,int r,int L,int R,int top);
 
 
inline long long gcd(long long  x,long long  y)
{
	while(y) y^=x^=y^=x%=y;
	return x;
}
inline long long read()
{
	long long ans=0;
	char c=getchar();
	while(c=='\n'||c==' ') c=getchar();
	while(c>='0'&&c<='9') ans=ans*10+c-'0',c=getchar();
	return ans;
}
inline long long myabs(long long z)
{
	if(z<0) return -z;
	else return z; 
}
inline bool check(int l)
{
	long long g,mx=0,x;
	for(int i=1;i<=n-l+1;i++)
	{
		g=query(i,i+l-2,1,n,1);
		mx=max(mx,g);
	}
	return mx>=2;
}
inline long long build(int l,int r,int top)
{
	if(l==r) return tree[top]=sub[l];
	int mid=l+r>>1;
	build(l,mid,top*2);
	build(mid+1,r,top*2+1);
	return tree[top]=gcd(tree[top*2],tree[top*2+1]);
}
inline long long query(int l,int r,int L,int R,int top)
{
	if(l==L&&r==R) return tree[top];
	int MID=L+R>>1;
	if(MID>=r) return query(l,r,L,MID,top*2);
	else if(MID+1<=l) return query(l,r,MID+1,R,top*2+1);
	else return gcd(query(l,MID,L,MID,top*2),query(MID+1,r,MID+1,R,top*2+1));
}
int main()
{
	int t;
	t=read();
	while(t--)
	{
		n=read();
		for(int i=1;i<=n;i++) a[i]=read();
		
		
		for(int i=2;i<=n;i++) sub[i-1]=myabs(a[i]-a[i-1]);
		
		
		build(1,n,1);
		int l=1,r=n,mid=l+r+1>>1;
		while(l<r)
		{
			if(check(mid)) l=mid;
			else r=mid-1;
			mid=l+r+1>>1;
		}
		printf("%d\n",l);
	}
}

主席树

#include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>
using namespace std;

const int N=100010;

struct Node{
int l,r;
int cnt;
}tr[N*4+N*17];

vector <int> num;
int a[N],idx,root[N];

int finx(int x)
{
    return lower_bound(num.begin(),num.end(),x)-num.begin();
}

int intree(int p,int l,int r,int x)
{
    int q=++idx;
    tr[q]=tr[p];
    if(l==r)
    {
        tr[q].cnt++;
        return q;
    }
    int mid=l+r>>1;
    if(x<=mid) tr[q].l=intree(tr[p].l,l,mid,x);
    else tr[q].r=intree(tr[p].r,mid+1,r,x);
    tr[q].cnt=tr[tr[q].l].cnt+tr[tr[q].r].cnt;
    return q;
}

int build(int l,int r)
{
    int p=++idx;
    if(l==r) return p;
    int mid=l+r>>1;
    tr[p].l=build(l,mid);
    tr[p].r=build(mid+1,r);
    return p;
}

int quary(int p,int q,int l,int r,int k)
{
    if(l==r) return l;
    int cnt=tr[tr[q].l].cnt-tr[tr[p].l].cnt;
    int mid=l+r>>1;
    if(cnt>=k) return quary(tr[p].l,tr[q].l,l,mid,k);
    else return quary(tr[p].r,tr[q].r,mid+1,r,k-cnt);
}

int main()
{
    int n,m;
    cin>>n>>m;
    for(int i=1;i<=n;i++)
    {
        scanf("%d",a+i);
        num.push_back(a[i]);
    }
    sort(num.begin(),num.end());
    num.erase(unique(num.begin(),num.end()),num.end());
    root[0]=build(0,num.size()-1);
    for(int i=1;i<=n;i++)
        root[i]=intree(root[i-1],0,num.size()-1,finx(a[i]));
    while(m--)
    {
        int l,r,k;
        scanf("%d%d%d",&l,&r,&k);
        printf("%d\n",num[quary(root[l-1],root[r],0,num.size()-1,k)]);
    }
}

这不是一棵树，但还是想拿过来作为cf冲蓝的纪念

#include<iostream>
#include<cmath>
using namespace std;
const int N=100010;
int fa[2][N];
int ans[N][2],cnt;
int hub[2][N];
int find(int k,int x)
{
    if(x!=fa[k][x]) return fa[k][x]=find(k,fa[k][x]);
    return x;
}
void link(int k,int x,int y)
{
    int p=find(k,x);
    int q=find(k,y);
    if(p>q) swap(p,q);
    fa[k][q]=p;
}
int main()
{
    int n,m1,m2;
    cin>>n>>m1>>m2;
    for(int i=1;i<=n;i++) fa[0][i]=fa[1][i]=i;

    for(int i=1;i<=m1;i++)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        link(0,x,y);
    }
    for(int i=1;i<=m2;i++)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        link(1,x,y);
    }
    for(int i=2;i<=n;i++)
    {
        if(find(0,i)!=1&&find(1,i)!=1)
        {
            ans[++cnt][0]=1;
            ans[cnt][1]=i;
            link(0,1,i);
            link(1,1,i);
        }
    }
    int cnt1_0=0,cnt0_1=0;
    for(int i=1;i<=n;i++) if(find(0,i)==1&&find(1,i)!=1) hub[0][++cnt1_0]=i;
    for(int i=1;i<=n;i++) if(find(0,i)!=1&&find(1,i)==1) hub[1][++cnt0_1]=i;
    hub[0][0]=1;
    hub[1][0]=1;
    while(hub[0][0]<=cnt1_0&&hub[1][0]<=cnt0_1)
    {
        link(0,hub[0][hub[0][0]],hub[1][hub[1][0]]);
        link(1,hub[0][hub[0][0]],hub[1][hub[1][0]]);
        ans[++cnt][0]=hub[0][hub[0][0]];
        ans[cnt][1]=hub[1][hub[1][0]];
        while(hub[0][0]<=cnt1_0&&!(find(0,hub[0][hub[0][0]])==1&&find(1,hub[0][hub[0][0]])!=1))
        hub[0][0]++;
        while(hub[1][0]<=cnt0_1&&!(find(0,hub[1][hub[1][0]])!=1&&find(1,hub[1][hub[1][0]])==1))
        hub[1][0]++;
    }

    cout<<cnt<<endl;
    for(int i=1;i<=cnt;i++)
    {
        printf("%d %d\n",ans[i][0],ans[i][1]);
    }
}