分块+莫队
#include<cstdio> #include<cstring> #include<algorithm> using namespace std; /*分块*/ #include<cmath> const int N=10; int pos[N],n,blk; void fenkuai(){ scanf("%d",&n); blk=(int)(double(n)); for(int i=1;i<=n;i++) pos[i]=(i-1)/blk+1; } /*莫队*/ int ans=0; struct qujian{ int le,ri,ans; }q[N]; bool cmp(const qujian &a,const qujian &b){ return pos[a.le]<pos[b.le]||(pos[a.le]==pos[b.le]&&a.ri<b.ri); } void update(int pos,int val){ } void modui(){ scanf("%d",&n); fenkuai(); for(int i=1;i<=n;i++) scanf("%d%d",&q[i].le,&q[i].ri); sort(q+1,q+n+1,cmp); int le,ri; le=ri=0; for(int i=1;i<=n;i++){ while(ri>q[i].ri){ update(ri,-1); ri--; } while(ri<q[i].ri){ update(ri+1,1); ri++; } while(le<q[i].le){ update(le,-1); le++; } while(le>q[i].le){ update(le-1,1); le--; } q[i].ans=ans; } /*...*/ }
字符串：
#include<cstdio> #include<cstring> #include<algorithm> using namespace std; const int N=10; /*kmp*/ int lens,lenp,nxt[N]; char s[N],p[N]; void get_nxt(){ int i=0,j=-1; nxt[0]=-1; while(i<lenp){ if(j==-1||p[i]==p[j]){ i++,j++; nxt[i]=j; } else j=nxt[j]; } } void kmp(){ int i=0,j=0; while(i<lens){ if(j==-1||s[i]==p[j]){ i++,j++; if(j==lenp){ /*success*/ j=nxt[j]; } } else j=nxt[j]; } } int main(){ scanf("%s%s",s,p); lens=strlen(s),lenp=strlen(p); get_nxt(); kmp(); return 0; } /*manacher*/ int pal[N]; void fixs(){ /* "aba" -> "-#a#b#a#+" */ } void manacher(){ int id,mx=0; for(int i=1;i<=lens;i++){ if(mx>=i) pal[i]=min(pal[2*id-i],mx-i+1); //else pal[i]=1; while(s[i+pal[i]]==s[i-pal[i]]) pal[i]++; if(pal[i]>mx) mx=pal[i],id=i; } } int main(){ scanf("%s",s); lens=strlen(s); fixs(); manacher(); return 0; }
数据结构
#include<cstdio> #include<cstring> #include<algorithm> using namespace std; const int N=10; /*左偏树(大根堆) + 并查集(路径压缩) */ int n,fa[N]; struct node{ int ls,rs; int dis,key; }tr[N]; int getfa(int x){ if(fa[x]==x) return x; return fa[x]=getfa(fa[x]); } int merge(int a,int b){ if(a==0) return b; if(b==0) return a; if(tr[a].key<tr[b].key) swap(a,b); tr[a].rs=merge(tr[a].rs,b); if(tr[tr[a].ls].dis<tr[tr[a].rs].dis) swap(tr[a].ls,tr[a].rs); tr[a].dis=tr[tr[a].rs].dis+1; return a; } int del(int a){ int tmp=merge(tr[a].ls,tr[a].rs); fa[getfa(a)]=tmp; fa[fa[getfa(a)]]=tmp; return tmp; } int main(){ tr[0].dis=-1,tr[0].key=0;//(small heap)tr[0].key=INF; scanf("%d",&n); for(int i=1;i<=n;i++) scanf("%d",&tr[i].key); for(int i=1;i<=n;i++) fa[i]=i; int q,opt,x,y; scanf("%d",&q); while(q--){ scanf("%d",&opt); if(opt==0){ scanf("%d%d",&x,&y); if(getfa(x)==getfa(y)) continue; int tmp=merge(getfa(x),getfa(y)); fa[getfa(x)]=fa[getfa(y)]=tmp; printf("%d ",tmp); } else{ scanf("%d",&x); printf("%d ",del(getfa(x))); } } return 0; }
#include<queue> struct cmp{ bool operator()(const Type &_a,const Type &_b){ return _a>_b;//小根堆 } }; priority_queue<Type,vector<Type>,cmp> q;
图论
#include<queue> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; const int N=100000+5; /*dijkstra(spfa)+heap(曾一直以为是spfa)*/ int s=1,n,m,dis[N]; bool exi[N]; int head[N],to[N*2],val[N*2],nxt[N*2],hh=0; struct cmp{ bool operator()(const int &a,const int &b){ return dis[a]>dis[b]; } }; priority_queue<int,vector<int>,cmp> q; void spfa(){ memset(dis,0x3f,sizeof(dis)); memset(exi,0,sizeof(exi)); while(!q.empty()) q.pop(); dis[s]=0,exi[s]=1; q.push(s); while(!q.empty()){ int u=q.top();q.pop(); exi[u]=0; for(int i=head[u];i;i=nxt[i]){ int v=to[i]; if(dis[v]>dis[u]+val[i]){ dis[v]=dis[u]+val[i]; if(!exi[v]){ q.push(v); exi[v]=1; } } } } } void adde(int a,int b,int v){ hh++; to[hh]=b; val[hh]=v; nxt[hh]=head[a]; head[a]=hh; } int main(){ scanf("%d%d",&n,&m); int u,v,w; for(int i=1;i<=m;i++){ scanf("%d%d%d",&u,&v,&w); adde(u,v,w),adde(v,u,w); } spfa(); for(int i=1;i<=n;i++) printf("%d ",dis[i]); return 0; }
bool find(int u){ for(int i=head[u];i;i=nxt[i]){ int v=to[i]; if(vis[v]) continue; vis[v]=1; if(bl[v]==0||find(bl[v])){ bl[v]=u; return true; } } return false; } int main(){ /*...*/ int cnt=0; for(int i=1;i<=n;i++){ memset(vis,0,sizeof(vis));//可用时间戳优化 if(find(i)) cnt++; } /*...*/ }
数论
int gcd(int a,int b){ return b?gcd(b,a%b):a; } void exgcd(int a,int b,int &x,int &y){ if(b==0){ x=1,y=0;return; } int x0,y0; exgcd(b,a%b,x0,y0); x=y0; y=x0-(a/b)*y0; }
#include<cstdio> #include<cstring> #include<algorithm> using namespace std; const int N=10; /*线性筛(莫比乌斯函数+欧拉函数)*/ int n; int prime[N],cntp,phi[N],mui[N]; bool notp[N]; void init(){ notp[1]=1; phi[1]=1,mui[1]=1; for(int i=2;i<=n;i++){ if(!notp[i]){ prime[++cntp]=i; phi[i]=i-1; mui[i]=-1; } for(int j=1;j<=cntp&&i*prime[j]<=n;j++){ if(i%prime[j]==0){ phi[i*prime[j]]=phi[i]*prime[j]; mui[i*prime[j]]=0; break; } phi[i*prime[j]]=phi[i]*(prime[j]-1); mui[i*prime[j]]=-mui[i]; notp[i*prime[j]]=1; } } } /*高斯消元*/ #include<cmath> const double eps=1e-8; int n,m;//n项 m方程 double g[N][N],ans[N]; void gauss(){ int cnt=0; for(int k=1;k<=n;k++){//第k列 int j=-1; for(int i=cnt+1;i<=m;i++) if(fabs(g[i][k])>eps){ j=i;break; } if(j==-1) continue; for(int i=1;i<=n+1;i++) swap(g[cnt+1][i],g[j][i]); for(j=1;j<=m;j++){ if(j==cnt+1) continue;//! if(fabs(g[j][k])<eps) continue; double r=g[j][k]/g[cnt+1][k]; for(int i=1;i<=n+1;i++) g[j][i]-=r*g[cnt+1][i]; } cnt++; } for(int i=cnt+1;i<=m;i++){ if(fabs(g[i][n+1])>eps) printf("no solution! "); } if(cnt<n){ printf("more than one solution! "); return; } for(int i=1;i<=cnt;i++) ans[i]=g[i][n+1]/g[i][i]; } int main(){ scanf("%d%d",&n,&m); for(int i=1;i<=m;i++) for(int j=1;j<=n+1;j++) scanf("%lf",&g[i][j]); gauss(); for(int i=1;i<=n;i++) printf("%.2lf ",ans[i]); return 0; }
Type power(Type a,Type b){ Type rt=1; for(;b;b>>=1,a=a*a%mod) if(b&1) rt=rt*a%mod; return rt; }
dp
int dfs(int pos,/*int some_ifo,*/bool limit/*,bool zero*/){ if(pos==0) return 1; if((!limit)/*&&(!zero)*/&&f[pos]!=-1) return f[pos]; int st=limit?k[pos]:9; int ans=0; for(int i=0;i<=st;i++){ /*if(some_limit)*/ ans+=dfs(pos-1,/**/,limit&&i==st/*,zero&&i==0*/); } if((!limit)/*&&(!zero)*/) f[pos]=ans; return ans; }
高精度
#include<cstdio> #include<cstring> #include<algorithm> using namespace std; const int N=100000+5; struct Type{ int a[N],len; }; void read(Type &res){ char ch=0; res.a[0]=1,res.len=0; while(ch<'0'||ch>'9'){if(ch=='-')res.a[0]=-1;ch=getchar();} while(ch>='0'&&ch<='9'){res.a[++res.len]=ch-'0';ch=getchar();} for(int i=1;i<=res.len/2;i++) swap(res.a[i],res.a[res.len-i+1]); } void print(const Type &pr){ if(pr.a[0]==-1) printf("-"); for(int i=pr.len;i>=1;i--) printf("%d",pr.a[i]); } Type operator +(Type _a,Type _b){ Type _c; _c.len=max(_a.len,_b.len); int tmp=0; for(int i=1;i<=min(_a.len,_b.len);i++){ tmp=_a.a[i]+_b.a[i]+tmp; _c.a[i]=tmp%10; tmp/=10; } for(int i=min(_a.len,_b.len)+1;i<=_c.len;i++){ tmp=_a.len>_b.len?_a.a[i]+tmp:_b.a[i]+tmp; _c.a[i]=tmp%10; tmp/=10; } if(tmp) _c.a[++_c.len]=tmp; return _c; } Type operator -(Type _a,Type _b){ Type _c; _c.len=_a.len; for(int i=1;i<=_b.len;i++){ _c.a[i]=_a.a[i]-_b.a[i]; if(_c.a[i]<0) _c.a[i]+=10,_a.a[i+1]--; } for(int i=_b.len+1;i<=_a.len;i++) _c.a[i]=_a.a[i]; while(_c.a[_c.len]==0) _c.len--; return _c; } Type a,b; int main(){ read(a),read(b); print(a-b); return 0; }