模版题目的集合
一大波模版题正在来袭
难度不一定递增，但应该是大致递增的难度。
【模板】快速读入
#include<bits/stdc++.h>
using namespace std;
int sum;
int in(){
int k=0,f=1;
char c=getchar_unlocked();
while(c<'0'||c>'9') {
if(c=='-')f=-1;
c=getchar_unlocked();
}
while(c>='0'&&c<='9')k=k*10+c-'0',c=getchar_unlocked();
return k*f;
}
void out(int x){
if(x<0)putchar('-'),x=-x;
if(x<10)putchar(x+'0');
else out(x/10),putchar(x%10+'0');
}
signed main(){
int n=in();
while(n--)sum+=in();
out(sum);
}
【模板】栈
#include<bits/stdc++.h>
#define int unsigned long long
using namespace std;
int n;
int T;
signed main(){
ios::sync_with_stdio(0);
cin>>T;
while(T--){
cin>>n;
stack<int>t;
while(n--){
string s;
cin>>s;
if(s=="push"){
int x;
cin>>x;
t.push(x);
}
else if(s=="query"){
if(t.empty())cout<<"Anguei!\n";
else cout<<t.top()<<'\n';
}
else if(s=="pop"){
if(t.empty())cout<<"Empty\n";
else t.pop();
}
else cout<<t.size()<<'\n';
}
}
}
【模板】快速幂
#include<bits/stdc++.h>
#define int long long
using namespace std;
int a,b,p;
int T;
signed main(){
ios::sync_with_stdio(0);
cin>>a>>b>>p;
int k=b;
int kk=a;
int ans=1;
while(b){
if(b&1)ans=(ans*a)%p;
a=(a*a)%p;
b>>=1;
}
cout<<kk<<'^'<<k<<" mod "<<p<<'='<<ans;
}
【模板】队列
#include<bits/stdc++.h>
using namespace std;
int n;
int T;
queue<int>q;
signed main(){
ios::sync_with_stdio(0);
cin>>T;
while(T--){
int op;
cin>>op;
if(op==1){
int x;
cin>>x;
q.push(x);
}
else if(op==2){
if(q.empty())cout<<"ERR_CANNOT_POP\n";
else q.pop();
}
else if(op==3){
if(q.empty())cout<<"ERR_CANNOT_QUERY\n";
else cout<<q.front()<<'\n';
}
else{
cout<<q.size()<<'\n';
}
}
}
【模板】排序
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+5;
int n;
int a[N];
signed main(){
ios::sync_with_stdio(0);
cin>>n;
for(int i=1;i<=n;i++)cin>>a[i];
sort(a+1,a+1+n);
for(int i=1;i<=n;i++)cout<<a[i]<<' ';
}
【模板】Floyd
#include<bits/stdc++.h>
#define int long long
using namespace std;
const int M=5e3+5;
const int INF=1e9+5;
int a[M][M];
int n,m;
int T;
signed main(){
ios::sync_with_stdio(0);
cin>>n>>m;
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
a[i][j]=INF;
}
}
int u,v,w;
while(m--){
cin>>u>>v>>w;
a[u][v]=min(a[u][v],w);
a[v][u]=min(a[v][u],w);
}
for(int k=1;k<=n;k++){
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
a[i][j]=min(a[i][j],a[i][k]+a[k][j]);
}
}
}
for(int i=1;i<=n;i++){
a[i][i]=0;
for(int j=1;j<=n;j++){
cout<<a[i][j]<<' ';
}
cout<<'\n';
}
}
【模板】字符串哈希
#include<bits/stdc++.h>
using namespace std;
const int N=1e4+5;
const int p=53;
const int mod=1e9+7;
int a[N];
char s[N];
int l[N];
int n;
int ans;
int cal(char a[]){
int n=strlen(a);
l[0]=0;
for(int i=1;i<=n;i++)l[i]=(l[i-1]*p+int(a[i]))%mod;
return l[n];
}
signed main(){
scanf("%d",&n);
for(int i=1;i<=n;i++){
scanf("%s",s+1);
a[i]=cal(s+1);
}
sort(a+1,a+n+1);
for(int i=1;i<=n;i++){
if(a[i]!=a[i-1])ans++;
}
printf("%d",ans);
}
【模板】拓扑排序 / 家谱树
#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5;
int n;
vector<int>a[N];
int rd[N];
int cnt,f[N];
void topsort(){
queue<int>q;
for(int i=1;i<=n;i++)if(rd[i]==0)q.push(i);
while(!q.empty()){
int x=q.front();
q.pop();
printf("%d ",x);
for(int i=0;i<a[x].size();i++){
int v=a[x][i];
if(--rd[v]==0){
q.push(v);
}
}
}
}
signed main(){
scanf("%d",&n);
for(int i=1;i<=n;i++){
int x;
while(1){
scanf("%d",&x);
if(x==0)break;
a[i].push_back(x);
rd[x]++;
}
}
topsort();
}
【模板】单调队列
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+5;
int a[N];
int q1[N+N];
int q2[N+N];
int head,tail;
int n,m;
signed main(){
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++)scanf("%d",&a[i]);
for(int i=1;i<=n;i++){
while(head<=tail&&q1[head]+m<=i)head++;
while(head<=tail&&a[i]<a[q1[tail]])tail--;
q1[++tail]=i;
if(i>=m)printf("%d ",a[q1[head]]);
}
printf("\n");
for(int i=1;i<=n;i++){
while(head<=tail&&q2[head]+m<=i)head++;
while(head<=tail&&a[i]>a[q2[tail]])tail--;
q2[++tail]=i;
if(i>=m)printf("%d ",a[q2[head]]);
}
}
【模板】单调栈
#include<bits/stdc++.h>
using namespace std;
const int N=3e6+5;
int a[N];
int t[N];
int n;
int head;
signed main(){
scanf("%d",&n);
for(int i=n;i>=1;i--)scanf("%d",&a[i]);
stack<int> k;
for(int i=1;i<=n;i++){
while(head>0&&a[t[head]]<=a[i])head--;
if(head==0)k.push(0);
else k.push(n-t[head]+1);
t[++head]=i;
}
while(!k.empty()){
printf("%d ",k.top());
k.pop();
}
}
【模板】三分 | 函数
#include<bits/stdc++.h>
using namespace std;
typedef long double db;
const int N=1e6+5;
const db eps=1e-11;
int n,m;
int a[N],b[N],c[N];
int T;
db check(db x){
db ans=a[1]*x*x+b[1]*x+c[1];
for(int i=2;i<=n;i++)ans=max(ans,a[i]*x*x+b[i]*x+c[i]);
return ans;
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(nullptr);
cout.tie(nullptr);
cin>>T;
while(T--){
cin>>n;
for(int i=1;i<=n;i++)cin>>a[i]>>b[i]>>c[i];
db l=0,r=1000;
db mid1,mid2;
while(r-l>eps){
mid1=l+(r-l)/3.0;
mid2=r-(r-l)/3.0;
if(check(mid1)>check(mid2))l=mid1;
else r=mid2;
}
printf("%.4Lf\n",check(l));
}
}
【模板】字典树
#include<bits/stdc++.h>
using namespace std;
const int N=3e6+5;
int t;
int n,m;
int ch[N][124];
int cnt[N];
int idx=0;
void in(string s){
int p=0;
for(int i=0;i<s.length();i++){
int j=int(s[i]);
if(!ch[p][j])ch[p][j]=++idx;
p=ch[p][j];
cnt[p]++;
}
}
int out(string s){
int p=0;
for(int i=0;i<s.length();i++){
int j=int(s[i]);
if(!ch[p][j])return 0;
p=ch[p][j];
}
return cnt[p];
}
signed main(){
scanf("%d",&t);
while(t--){
scanf("%d%d",&n,&m);
string s;
for(int i=0;i<=idx;i++){
cnt[i]=0;
for(int j=0;j<=123;j++){
ch[i][j]=0;
}
}
idx=0;
for(int i=1;i<=n;i++){
cin>>s;
in(s);
}
for(int i=1;i<=m;i++){
cin>>s;
printf("%d\n",out(s));
}
}
}
【模板】并查集
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+5;
int f[N];
int n,m;
int T;
int find(int x){
if(f[x]!=x)f[x]=find(f[x]);
return f[x];
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(nullptr);
cout.tie(nullptr);
cin>>n>>m;
for(int i=1;i<=n;i++)f[i]=i;
while(m--){
int op;
cin>>op;
int x,y;
cin>>x>>y;
if(op==1){
f[find(x)]=find(y);
}
else{
if(f[find(x)]==f[find(y)])cout<<"Y\n";
else cout<<"N\n";
}
}
}
【模板】最小生成树
#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=2e6+5;
struct node{
int u,v,w;
}a[N];
int f[N];
int cnt;
int n,m;
int find(int x){
if(f[x]!=x)f[x]=find(f[x]);
return f[x];
}
bool cmp(node a,node b){
return a.w<b.w;
}
int s(){
sort(a+1,a+1+cnt,cmp);
for(int i=1;i<=cnt;i++)f[i]=i;
int sum=0;
for(int i=1;i<=cnt;i++){
int u=a[i].u;
int v=a[i].v;
int w=a[i].w;
if(find(u)==find(v))continue;
else{
sum+=w;
f[find(u)]=find(v);
}
}
return sum;
}
int vis[N];
vector<int>vs[N];
void dfs(int x){
vis[x]=1;
for(int i=0;i<vs[x].size();i++){
if(vis[vs[x][i]]==0)dfs(vs[x][i]);
}
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(nullptr);
cout.tie(nullptr);
cin>>n>>m;
while(m--){
int x,y,z;
cin>>x>>y>>z;
vs[x].push_back(y);
vs[y].push_back(x);
a[++cnt]=node{x,y,z};
}
dfs(1);
for(int i=1;i<=n;i++)if(!vis[i]){
cout<<"orz";
return 0;
}
cout<<s();
}
【模板】负环
#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5;
struct node{
int to,dis;
};
int T;
vector<node>a[N];
int dis[N];
int vis[N];
int cnt[N];
int n,m;
queue<int>q;
bool spfa(){
for(int i=1;i<=n;i++)dis[i]=2147483647;
dis[1]=0;
q.push(1);
vis[1]=1;
while(!q.empty()){
int x=q.front();
q.pop();
vis[x]=0;
for(int i=0;i<a[x].size();i++){
int v=a[x][i].to;
int w=a[x][i].dis;
if(dis[v]>dis[x]+w){
dis[v]=dis[x]+w;
if(vis[v]==0){
vis[v]=1;
q.push(v);
cnt[v]++;
}
if(cnt[v]>n)return true;
}
}
}
return false;
}
signed main(){
scanf("%d",&T);
while(T--){
scanf("%d%d",&n,&m);
memset(vis,0,sizeof(vis));
memset(cnt,0,sizeof(vis));
while(!q.empty())q.pop();
for(int i=1;i<=n;i++)a[i].clear();
for(int i=1;i<=m;i++){
int u,v,w;
scanf("%d%d%d",&u,&v,&w);
a[u].push_back(node{v,w});
if(w>=0)a[v].push_back(node{u,w});
}
if(spfa())printf("YES\n");
else printf("NO\n");
}
}
【模板】堆
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+5;
int a[N];
int n;
int T;
priority_queue<int,vector<int>,greater<int> >q;
signed main(){
ios::sync_with_stdio(0);
cin.tie(nullptr);
cout.tie(nullptr);
cin>>T;
while(T--){
int op;
cin>>op;
if(op==1){
int x;
cin>>x;
q.push(x);
}
else if(op==2){
cout<<q.top()<<'\n';
}
else q.pop();
}
}
【模板】单源最短路径
#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=1e5+5;
int n,m,s;
struct node{
int to,dis;
friend bool operator <(node a,node b){
return a.dis>b.dis;
}
};
priority_queue<node>q;
vector<node>a[N];
int dis[N];
int vis[N];
void dij(){
for(int i=1;i<=n;i++)dis[i]=INT_MAX;
dis[s]=0;
q.push(node{s,0});
while(!q.empty()){
node t=q.top();
q.pop();
int x=t.to;
if(vis[x]==1)continue;
vis[x]=1;
for(int i=0;i<a[x].size();i++){
int y=a[x][i].to;
int z=a[x][i].dis;
dis[y]=min(dis[y],dis[x]+z);
if(vis[y]==0)q.push(node{y,dis[y]});
}
}
}
signed main(){
scanf("%lld%lld%lld",&n,&m,&s);
int u,v,w;
for(int i=1;i<=m;i++){
scanf("%lld%lld%lld",&u,&v,&w);
a[u].push_back(node{v,w});
}
dij();
for(int i=1;i<=n;i++)printf("%lld ",dis[i]);
}
【模板】差分约束
#include<bits/stdc++.h>
using namespace std;
const int N=5e3+5;
struct node{
int to,dis;
};
vector<node>a[N];
int n,m;
int vis[N];
int dis[N];
int cnt[N];
queue<int>q;
bool spfa(){
for(int i=1;i<=n;i++)dis[i]=2147483647;
dis[0];
q.push(0);
vis[0]=1;
while(!q.empty()){
int x=q.front();
vis[x]=0;
q.pop();
for(int i=0;i<a[x].size();i++){
int v=a[x][i].to;
int w=a[x][i].dis;
if(dis[v]>dis[x]+w){
dis[v]=dis[x]+w;
if(vis[v]==0){
vis[v]=1;
cnt[v]++;
q.push(v);
}
if(cnt[v]>n)return true;
}
}
}
return false;
}
signed main(){
scanf("%d%d",&n,&m);
for(int i=1;i<=m;i++){
int u,v,w;
scanf("%d%d%d",&u,&v,&w);
a[v].push_back(node{u,w});
}
for(int i=1;i<=n;i++){
a[0].push_back(node{i,0});
}
if(spfa()){
printf("NO");
}
else{
for(int i=1;i<=n;i++)printf("%d ",dis[i]);
}
}
【模板】边双连通分量
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+5;
int n,m,k;
int T;
int dfn[N];
int low[N];
int idx;
int f[N];
int cnt;
int cntt;
vector<pair<int,int> >a[N];
vector<int>ans[N];
void dfs(int x,int fa){
dfn[x]=low[x]=++idx;
f[++cnt]=x;
for(int i=0;i<a[x].size();i++){
pair<int,int> y=a[x][i];
if(y.second==(fa^1))continue;
if(dfn[y.first]==0){
dfs(y.first,y.second);
low[x]=min(low[x],low[y.first]);
}
else{
low[x]=min(dfn[y.first],low[x]);
}
}
if(dfn[x]==low[x]){
ans[++cntt].push_back(x);
while(f[cnt]!=x)ans[cntt].push_back(f[cnt--]);
cnt--;
}
}
signed main(){
ios::sync_with_stdio(0);
cin>>n>>m;
for(int i=1;i<=m;i++){
int u,v;
cin>>u>>v;
a[u].push_back(make_pair(v,i<<1));
a[v].push_back(make_pair(u,i<<1|1));
}
for(int i=1;i<=n;i++){
if(!dfn[i])dfs(i,0);
}
cout<<cntt<<'\n';
for(int i=1;i<=cntt;i++){
cout<<ans[i].size()<<' ';
for(int j=0;j<ans[i].size();j++)cout<<ans[i][j]<<' ';
}
}
【模板】树状数组 1
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=5e5+5;
ll a[N];
ll f[N];
ll n,m;
int lowbit(ll x){
return x&-x;
}
void change(ll x,ll k){
while(x<=n)f[x]+=k,x+=lowbit(x);
}
ll out(ll x){
int sum=0;
while(x)sum+=f[x],x-=lowbit(x);
return sum;
}
signed main(){
scanf("%lld%lld",&n,&m);
for(int i=1;i<=n;i++){
scanf("%lld",&a[i]);
change(i,a[i]);
}
while(m--){
int op;
ll x,y;
scanf("%d",&op);
scanf("%lld%lld",&x,&y);
if(op==1){
change(x,y);
}
else{
printf("%lld\n",out(y)-out(x-1));
}
}
}
【模板】KMP
#include<bits/stdc++.h>
using namespace std;
const int N=5e6+5;
int ne[N];
char a[N];
char c[N];
signed main(){
cin>>c+1;
cin>>a+1;
int n=strlen(a+1);
int m=strlen(c+1);
ne[1]=0;
for(int i=2,j=0;i<=n;i++){
while(j&&a[i]!=a[j+1])j=ne[j];
if(a[i]==a[j+1])j++;
ne[i]=j;
}
for(int i=1,j=0;i<=m;i++){
while(j&&c[i]!=a[j+1])j=ne[j];
if(c[i]==a[j+1])j++;
if(j==n)printf("%d\n",i-n+1);
}
for(int i=1;i<=n;i++)printf("%d ",ne[i]);
}
【模板】树状数组 2
#include<bits/stdc++.h>
using namespace std;
const int N=5e5+5;
int a[N];
int f[N];
int n,m;
int lowbit(int x){
return x&(-x);
}
void change(int x,int k){
while(x<=n)f[x]+=k,x+=lowbit(x);
}
int c(int x){
int res=0;
while(x)res+=f[x],x-=lowbit(x);
return res;
}
signed main(){
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++){
scanf("%d",&a[i]);
}
while(m--){
int z;
scanf("%d",&z);
if(z==1){
int x,y,k;
scanf("%d%d%d",&x,&y,&k);
change(x,k);
change(y+1,-k);
}
else{
int x;
scanf("%d",&x);
printf("%d\n",a[x]+c(x));
}
}
}
【模板】线段树 1
#include<bits/stdc++.h>
#define int long long
#define lc p<<1
#define rc p<<1|1
using namespace std;
const int N=1e6+5;
const int M=1e3+5;
int n,m,k;
int T;
int a[N];
struct node{
int l,r,ans,add;
}f[4*N];
void build(int p,int l,int r){
f[p]={l,r,a[l],0};
if(l==r)return;
int mid=l+r>>1;
build(lc,l,mid);
build(rc,mid+1,r);
f[p].ans=f[lc].ans+f[rc].ans;
}
void down(int p){
if(f[p].add){
f[lc].ans+=(f[lc].r-f[lc].l+1)*f[p].add;
f[rc].ans+=(f[rc].r-f[rc].l+1)*f[p].add;
f[lc].add+=f[p].add;
f[rc].add+=f[p].add;
f[p].add=0;
}
}
void change(int p,int l,int r,int k){
if(f[p].l>=l&&f[p].r<=r){
f[p].ans+=(f[p].r-f[p].l+1)*k;
f[p].add+=k;
return;
}
int mid=f[p].l+f[p].r>>1;
down(p);
if(l<=mid)change(lc,l,r,k);
if(mid<r)change(rc,l,r,k);
f[p].ans=f[lc].ans+f[rc].ans;
}
int cha(int p,int l,int r){
if(f[p].l>=l&&f[p].r<=r){
return f[p].ans;
}
int mid=f[p].l+f[p].r>>1;
int ans=0;
down(p);
if(l<=mid)ans+=cha(lc,l,r);
if(mid<r)ans+=cha(rc,l,r);
return ans;
}
signed main(){
ios::sync_with_stdio(0);
cin>>n>>m;
for(int i=1;i<=n;i++){
cin>>a[i];
}
build(1,1,n);
int x,y,k;
while(m--){
int op;
cin>>op;
if(op==1){
cin>>x>>y>>k;
change(1,x,y,k);
}
else{
cin>>x>>y;
cout<<cha(1,x,y)<<'\n';
}
}
}
【模板】线段树 2
#include<bits/stdc++.h>
#define int long long
#define lc p<<1
#define rc p<<1|1
using namespace std;
const int N=1e6+5;
const int M=1e3+5;
int n,m,k,mod;
int T;
int a[N];
struct node{
int l,r,ans,add,mo;
}f[4*N];
void build(int p,int l,int r){
f[p]={l,r,a[l]%mod,0,1};
if(l==r)return;
int mid=l+r>>1;
build(lc,l,mid);
build(rc,mid+1,r);
f[p].ans=(f[lc].ans+f[rc].ans)%mod;
}
void down(int p){
f[lc].ans=((f[p].mo*f[lc].ans)%mod+((f[lc].r-f[lc].l+1)*f[p].add)%mod)%mod;
f[rc].ans=((f[p].mo*f[rc].ans)%mod+((f[rc].r-f[rc].l+1)*f[p].add)%mod)%mod;
f[lc].add=((f[lc].add*f[p].mo)%mod+f[p].add)%mod;
f[rc].add=((f[rc].add*f[p].mo)%mod+f[p].add)%mod;
f[lc].mo=(f[lc].mo*f[p].mo)%mod;
f[rc].mo=(f[rc].mo*f[p].mo)%mod;
f[p].add=0;
f[p].mo=1;
}
void change(int p,int l,int r,int k){
if(f[p].l>=l&&f[p].r<=r){
f[p].ans=(f[p].ans+(f[p].r-f[p].l+1)*k)%mod;
f[p].add=(f[p].add+k)%mod;
return;
}
int mid=f[p].l+f[p].r>>1;
down(p);
if(l<=mid)change(lc,l,r,k);
if(mid<r)change(rc,l,r,k);
f[p].ans=(f[lc].ans+f[rc].ans)%mod;
}
void mo(int p,int l,int r,int k){
if(f[p].l>=l&&f[p].r<=r){
f[p].ans=(f[p].ans*k)%mod;
f[p].mo=(f[p].mo*k)%mod;
f[p].add=(f[p].add*k)%mod;
return;
}
int mid=f[p].l+f[p].r>>1;
down(p);
if(l<=mid)mo(lc,l,r,k);
if(mid<r)mo(rc,l,r,k);
f[p].ans=(f[lc].ans+f[rc].ans)%mod;
}
int cha(int p,int l,int r){
if(f[p].l>=l&&f[p].r<=r){
return f[p].ans%mod;
}
int mid=f[p].l+f[p].r>>1;
int ans=0;
down(p);
if(l<=mid)ans=(ans+cha(lc,l,r))%mod;
if(mid<r)ans=(ans+cha(rc,l,r))%mod;
return ans;
}
signed main(){
ios::sync_with_stdio(0);
cin>>n>>m>>mod;
for(int i=1;i<=n;i++){
cin>>a[i];
}
build(1,1,n);
int x,y,k;
while(m--){
int op;
cin>>op;
if(op==1){
cin>>x>>y>>k;
mo(1,x,y,k);
}
else if(op==2){
cin>>x>>y>>k;
change(1,x,y,k);
}
else{
cin>>x>>y;
cout<<cha(1,x,y)<<'\n';
}
}
}
【模板】割点（割顶）
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+5;
int n,m;
int dfn[N];
int vis[N];
int low[N];
int cut[N];
vector<int>a[N];
int cnt;
int times;
void tarjan(int x,int root){
vis[x]=1;
dfn[x]=low[x]=++times;
int s=0;
for(int i=0;i<a[x].size();i++){
int y=a[x][i];
if(dfn[y]==0){
s++;
tarjan(y,root);
low[x]=min(low[x],low[y]);
if(x!=root&&low[y]>=dfn[x])cut[x]=1;
if(x==root&&s>=2)cut[x]=1;
}
else{
low[x]=min(low[x],dfn[y]);
}
}
}
main(){
scanf("%d%d",&n,&m);
int u,v;
for(int i=1;i<=m;i++){
scanf("%d%d",&u,&v);
a[u].push_back(v);
a[v].push_back(u);
}
for(int i=1;i<=n;i++)if(dfn[i]==0)tarjan(i,i);
int cnt=0;
for(int i=1;i<=n;i++)if(cut[i])cnt++;
printf("%d\n",cnt);
for(int i=1;i<=n;i++)if(cut[i])printf("%d ",i);
}
【模板】点双连通分量
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+5;
int n,m,k;
int T;
vector<int>a[N];
int low[N],dfn[N];
int tt;
int cnt;
int top;
int t[N];
vector<int>f[N];
void dfs(int u,int fa){
int son=0;
low[u]=dfn[u]=++tt;
t[++top]=u;
for(int i=0;i<a[u].size();i++){
int v=a[u][i];
if(dfn[v]==0){
son++;
dfs(v,u);
low[u]=min(low[u],low[v]);
if(low[v]>=dfn[u]){
cnt++;
while(t[top+1]!=v)f[cnt].push_back(t[top--]);
f[cnt].push_back(u);
}
}
else if(v!=fa){
low[u]=min(low[u],dfn[v]);
}
}
if(fa==0&&son==0)f[++cnt].push_back(u);
}
signed main(){
ios::sync_with_stdio(0);
cin>>n>>m;
int u,v;
for(int i=1;i<=m;i++){
cin>>u>>v;
a[u].push_back(v);
a[v].push_back(u);
}
for(int i=1;i<=n;i++){
if(dfn[i])continue;
dfs(i,0);
}
cout<<cnt<<'\n';
for(int i=1;i<=cnt;i++){
cout<<f[i].size()<<' ';
for(int j=0;j<f[i].size();j++)cout<<f[i][j]<<' ';
cout<<'\n';
}
}
【模板】三维偏序
#include<bits/stdc++.h>
#define xx x&-x
using namespace std;
const int N=1e5+5;
const int M=1e3+5;
int n,m,k;
int T;
struct node{
int a,b,c,cnt,ans;
}e[N],t[N];
int ans[N];
int bit[N];
bool cmpA(node a,node b){
return a.a<b.a||(a.a==b.a&&a.b<b.b)||(a.a==b.a&&a.b==b.b&&a.c<b.c);
}
bool cmpB(node a,node b){
return a.b<b.b||(a.b==b.b&&a.c<b.c);
}
void update(int x,int v){
while(x<=k){
bit[x]+=v;
x+=xx;
}
}
int query(int x){
int res=0;
while(x){
res+=bit[x];
x-=xx;
}
return res;
}
void cdq(int l,int r){
if(l==r)return;
int mid=l+r>>1;
cdq(l,mid);
cdq(mid+1,r);
sort(e+l,e+mid+1,cmpB);
sort(e+mid+1,e+r+1,cmpB);
int i=l,j=mid+1;
while(j<=r){
while(i<=mid&&e[i].b<=e[j].b){
update(e[i].c,e[i].cnt);
i++;
}
e[j].ans+=query(e[j].c);
j++;
}
for(int p=l;p<=i-1;p++)update(e[p].c,-e[p].cnt);
}
signed main(){
ios::sync_with_stdio(0);
cin>>n>>k;
for(int i=1;i<=n;i++){
cin>>e[i].a>>e[i].b>>e[i].c;
e[i].cnt=1;
}
sort(e+1,e+1+n,cmpA);
int m=1;
for(int i=2;i<=n;i++){
if(e[i].a==e[m].a&&e[i].b==e[m].b&&e[i].c==e[m].c){
e[m].cnt++;
}
else{
e[++m]=e[i];
}
}
cdq(1,m);
for(int i=1;i<=m;i++)ans[e[i].ans+e[i].cnt]+=e[i].cnt;
for(int i=1;i<=n;i++)cout<<ans[i]<<'\n';
}