【模板】各类我会的傻逼算法模板合集（建设中
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最大流dinic
const int M=100005,N=2*1234; struct edge{ int to,next,cap; }e[M]; int cnt=1,last[N],h[N]; void insert(int a,int b,int c){ e[++cnt]=(edge){b,last[a],c};last[a]=cnt; e[++cnt]=(edge){a,last[b],c};last[b]=cnt; } bool bfs(int s,int t){ memset(h,-1,sizeof(h)); queue<int>q; q.push(s);h[s]=0; while(!q.empty()){ int c=q.front();q.pop(); for(int i=last[c];i;i=e[i].next){ if(e[i].cap&&h[e[i].to]==-1){ h[e[i].to]=h[c]+1; q.push(e[i].to); } } } return h[t]^(-1); } int dfs(int x,int t,int f){ if(x==t)return f; int used=0,w=0; for(int i=last[x];i;i=e[i].next){ if(h[e[i].to]==h[x]+1){ w=dfs(e[i].to,t,min(f-used,e[i].cap)); e[i].cap-=w; e[i^1].cap+=w; used+=w; if(used==f) return f; } } if(!used)h[x]=-1; return used; } int dinic(int s,int t){ int ans=0; while(bfs(s,t)){ int flow=dfs(s,t,inf); ans+=flow; if(ans>=inf)return ans; } return ans; }
FFT
struct cpx { double r,i; cpx(double real=0.0,double image=0.0) {r=real;i=image;} cpx operator +(const cpx w) {return cpx(r+w.r,i+w.i);} cpx operator -(const cpx w) {return cpx(r-w.r,i-w.i);} cpx operator *(const cpx w) {return cpx(r*w.r-i*w.i,r*w.i+i*w.r);} }; cpx a[N],b[N]; cpx epsilon[N],arti_epsilon[N]; void init_epsilon(int n){ double pi=acos(-1); for(int i=0;i!=n;i++){ epsilon[i]=cpx(cos(2.0*pi*i/n),sin(2.0*pi*i/n)); //arti_epsilon[i]=conj(epsilon[i]); arti_epsilon[i]=cpx(cos(2.0*pi*i/n),-sin(2.0*pi*i/n)); } } void rev(int n,cpx*t){ for(int i=0,j=0;i!=n;i++){ if(i>j)swap(t[i],t[j]); for(int l=n/2;(j^=l)<l;l>>=1); } } void dft(int n,cpx*x,cpx*w){ rev(n,x); for(int i=2;i<=n;i<<=1){ int m=i/2; for(int j=0;j<n;j+=i){ for(int k=0;k!=m;k++){ cpx t=x[j+m+k]*w[n/i*k]; x[j+m+k]=x[j+k]-t; x[j+k]=x[j+k]+t; } } } } cpx c[N]; void mul(cpx *a,cpx *b){ int A,B; A=gi;B=gi;++A,++B; for(int i=0;i<A;i++)a[i].r=gi; for(int i=0;i<B;i++)b[i].r=gi; int t=max(A,B); int n=1; for(;n<t*2;n<<=1); init_epsilon(n); dft(n,a,epsilon); dft(n,b,epsilon); // py trade for(int i=0;i<n;i++)c[i]=a[i]*b[i]; int nn=n;cout<<n; dft(n,c,arti_epsilon); for(int i=0;i<=A+B-1;i++)printf("%d ",(int)(c[i].r/nn+0.5)); }
树剖
namespace slpf{ #define N 123456 #define M 223456 struct edge{ int to,next; }e[M];int rt,cnt,last[N],top[N],siz[N],dep[N],fa[N],son[N],id[N],hp[N],idcnt=0,hpcnt=0; void insert(int a,int b){ e[++cnt]=(edge){b,last[a]}; last[a]=cnt; } void dfs1(int x){ siz[x]=1; for(int i=last[x];i;i=e[i].next){ int j=e[i].to; // fa[j]=x; dep[j]=dep[x]+1; dfs1(j); if(siz[j]>siz[son[x]])son[x]=j; } } void dfs2(int x,int t){ top[x]=t;id[++idcnt]=x;hp[x]=idcnt; if(son[x])dfs2(son[x],t); for(int i=last[x];i;i=e[i].next) if(e[i].to!=son[x])dfs2(e[i].to,e[i].to); } int tiao(int x,int d){ for(;fa[top[x]]&&dep[fa[top[x]]]>=d;x=fa[top[x]]); return id[hp[x]-dep[x]+d]; } int lca(int a,int b){ int f1=top[a],f2=top[b]; while(f1!=f2){ if(dep[f1]<dep[f2]) swap(f1,f2),swap(a,b); a=fa[f1]; f1=top[a]; } return dep[a]>dep[b]?b:a; } void debug(){ memset(dep,0,sizeof(dep));idcnt=0; memset(last,0,sizeof(last));cnt=0; memset(son,0,sizeof(son));memset(fa,0,sizeof(fa)); memset(siz,0,sizeof(siz)); int n=gi; for(int i=1;i<n;i++){ int a=gi,b=gi; insert(a,b); fa[b]=a; } int rat=1; while(fa[rat])rat=fa[rat]; rt=rat; dfs1(rt); dfs2(rt,rt); printf("%d\n",lca(gi,gi)); }; }
计算几何（只有凸包，未完成
const double eps=1e-8; int cmp(double x){ if(fabs(x)<eps)return 0; if(x>0)return 1; return -1; } struct point{ double x,y; point(){ } point(double a,double b):x(a),y(b){} void input(){ scanf("%lf%lf",&x,&y); } friend point operator+(point a,point b){return point(a.x+b.x,a.y+b.y);} friend point operator-(point a,point b){return point(a.x-b.x,a.y-b.y);} friend point operator*(point a,double b){return point(a.x*b,a.y*b);} friend point operator*(double a,point b){return point(a*b.x,a*b.y);} friend bool operator==(point a,point b){return !cmp(a.x-b.x)&&!cmp(a.y-b.y);} double norm(){return sqrt(x*x+y*y);} }; double det(point a,point b){return a.x*b.y-a.y*b.x;} double dot(point a,point b){return a.x*b.x+a.y*b.y;} double dist(point a,point b){return (a-b).norm();} struct line{ point a,b; line(point x,point y):a(x),b(y){} }; struct convex{ vector<point>P; convex(int Size=0){P.resize(Size);} }; bool lss(point a,point b){ return cmp(a.x-b.x<0)||(cmp(a.x-b.x)==0&&cmp(a.y-b.y)<0); } // checked by poj 1113 convex Graham(vector<point> a){ convex res(2*a.size()+5); sort(a.begin(),a.end(),lss); a.erase(unique(a.begin(),a.end()),a.end()); int m=0; for(int i=0;i<a.size();i++){ while(m>1&&cmp(det(res.P[m-1]-res.P[m-2],a[i]-res.P[m-2]))<=0)--m; res.P[m++]=a[i]; } int k=m;//上凸壳大小 for(int i=a.size()-2;i>=0;i--){ while(m>k&&cmp(det(res.P[m-1]-res.P[m-2],a[i]-res.P[m-2]))<=0)--m; res.P[m++]=a[i]; } res.P.resize(m-(a.size()>1)); return res; } void debug(){ int n,L; n=gi; vector<point>a(n); for(int i=0;i<a.size();i++){ a[i].input(); } }
SA
#define N 400005 struct Suffix_Array{ int s[N],sa[N],rk[N],SA[N],RK[N],v[N],h[N],len; int mn[N][19],lg[N]; void mul(int k,int *sa,int *rk,int *SA,int *RK){ for(int i=1;i<=len;i++) v[rk[sa[i]]]=i; for(int i=len;i;i--) if(sa[i]>k) SA[v[rk[sa[i]-k]]--]=sa[i]-k; for(int i=len-k+1;i<=len;i++) SA[v[rk[i]]--]=i; for(int i=1;i<=len;i++) RK[SA[i]]=RK[SA[i-1]]+(rk[SA[i]]!=rk[SA[i-1]]||rk[SA[i-1]+k]!=rk[SA[i]+k]); } void get_sa(int lim){ for(int i=1;i<=len;i++) v[s[i]]++; for(int i=1;i<=lim;i++) v[i]+=v[i-1]; for(int i=1;i<=len;i++) sa[v[s[i]]--]=i; for(int i=1;i<=len;i++) rk[sa[i]]=rk[sa[i-1]]+(s[sa[i-1]]!=s[sa[i]]); for(int k=1;k<=len;k<<=1) { mul(k,sa,rk,SA,RK);; memcpy(sa,SA,len+1<<2); memcpy(rk,RK,len+1<<2); } for(int k=0,j,i=1;i<=len;i++){ j=sa[rk[i]-1]; while(s[j+k]==s[i+k]) k++; h[rk[i]]=k;if(k) k--; } for(int i=1;i<=len;i++) mn[i][0]=h[i]; for(int j=1;(1<<j)<=len;j++) { for(int i=1;i+(1<<j)-1<=len;i++) mn[i][j]=min(mn[i][j-1],mn[i+(1<<j-1)][j-1]); } for(int i=2;i<=len;i++) lg[i]=lg[i>>1]+1; } int get_mn(int l,int r){ int t=lg[r-l+1]; return min(mn[l][t],mn[r-(1<<t)+1][t]); } int lcp(int x,int y){ if(x>y) swap(x,y); return get_mn(x+1,y); } }
