Models(Pascal)
KMP
var p,t:string; f:Array[0..255] of longint; m,n,i,j:longint; procedure getfail; begin f[1]:=1;f[2]:=1; for i:=2 to m do begin j:=f[i]; while (j>1)and(t[i]<>t[j])do j:=f[j]; if t[i]=t[j] then f[i+1]:=j+1 else f[i+1]:=1; end; end; begin readln(p); readln(t); n:=length(p); m:=length(t); getfail;//for str T[] j:=1; for i:=1 to n do begin while (j>1)and(p[i]<>t[j]) do j:=f[j]; if p[i]=t[j] then begin if j=m then writeln(i-m+1); inc(j); end; end; end.
LCA
type point=^rec; rec=record data:longint; next:point; end; const maxn=30000+100; var d:array[0..maxn] of longint; p:array[0..maxn,0..20] of longint; map:array[0..maxn] of point; i,n,m,x,y,last,log,ans:longint; k:point; procedure swap(var a,b:longint); var t:longint; begin t:=a;a:=b;b:=t; end; procedure dfs(u,fa:longint); var k:point; begin d[u]:=d[fa]+1; p[u,0]:=fa; log:=trunc(ln(n)/ln(2)); for i:=1 to log do p[u,i]:=p[p[u,i-1],i-1]; k:=map[u]; while k<>nil do begin if k^.data<>fa then dfs(k^.data,u); k:=k^.next; end; end; function lca(a,b:longint):longint; var del,i:longint; begin if d[a]>d[b] then swap(a,b); if d[a]<d[b] then begin del:=d[b]-d[a]; log:=trunc(ln(d[b])/ln(2)); for i:=log downto 0 do if (d[b]-(1 shl i))>=d[a] then b:=p[b,i]; end; if a<>b then begin log:=trunc(ln(d[b])/ln(2)); for i:=log downto 0 do if p[a,i]<>p[b,i] then begin a:=p[a,i];b:=p[b,i]; end; a:=p[a,0];b:=p[b,0]; end; exit(a); end; begin readln(n); fillchar(d,sizeof(d),0); for i:=1 to n-1 do begin readln(x,y); new(k); k^.data:=y; k^.next:=map[x]; map[x]:=k; new(k); k^.data:=x; k^.next:=map[y]; map[y]:=k; end; k:=map[1]; while k<>nil do begin dfs(k^.data,1); k:=k^.next; end; readln(m); last:=1; for i:=1 to m do begin readln(x); inc(ans,d[x]+d[last]-2*d[lca(x,last)]); last:=x; end; writeln(ans); end. //codevs 2370 type point=^rec; rec=record data:longint; next:point; end; link=^reco; reco=record p,dis:longint; next:link; end; const maxn=50000+10; var d,dep:array[0..maxn]of longint; distance:array[0..maxn] of link; p:array[0..maxn,0..20]of longint; map:array[0..maxn] of point; n,m,i,x,y,ans,last,log,dis:longint; k:point; kk:link; function get_dis(a,b:longint):longint; var kk:link; begin kk:=distance[a]; while kk<>nil do begin if kk^.p=b then exit(kk^.dis); kk:=kk^.next; end; end; procedure swap(var a,b:longint); var t:longint; begin t:=a;a:=b;b:=t; end; procedure dfs(u,fa:longint); var k:point; begin dep[u]:=get_dis(u,fa)+dep[fa]; d[u]:=d[fa]+1; p[u,0]:=fa; log:=trunc(ln(n)/ln(2)); for i:=1 to log do p[u,i]:=p[p[u,i-1],i-1]; k:=map[u]; while k<>nil do begin if k^.data<>fa then dfs(k^.data,u); k:=k^.next; end; end; function lca(a,b:longint):longint; var del,i:longint; begin if d[a]>d[b] then swap(a,b); if d[a]<d[b] then begin del:=d[b]-d[a]; log:=trunc(ln(d[b])/ln(2)); for i:=log downto 0 do if (d[b]-(1 shl i))>=d[a] then b:=p[b,i]; end; if a<>b then begin log:=trunc(ln(d[b])/ln(2)); for i:=log downto 0 do if p[a,i]<>p[b,i] then begin a:=p[a,i];b:=p[b,i]; end; a:=p[a,0];b:=p[b,0]; end; exit(a); end; begin fillchar(d,sizeof(d),0); readln(n); for i:=1 to n-1 do begin readln(x,y,dis); new(kk); kk^.p:=y; kk^.dis:=dis; kk^.next:=distance[x]; distance[x]:=kk; new(kk); kk^.p:=x; kk^.dis:=dis; kk^.next:=distance[y]; distance[y]:=kk; new(k); k^.data:=y; k^.next:=map[x]; map[x]:=k; new(k); k^.data:=x; k^.next:=map[y]; map[y]:=k; end; k:=map[1]; while k<>nil do begin dfs(k^.data,1); k:=k^.next; end; readln(m); last:=1; for i:=1 to m do begin readln(x,y); writeln(dep[x]+dep[y]-2*dep[lca(x,y)]); end; end.
并查集
var father:array[1..5000] of longint; i,j,k,p,n,m:longint; function getfather(v:longint):longint;//寻找根节点 begin if father[v]=v then exit(v); father[v]:=getfather(father[v]); exit(father[v]); end; procedure merge(x,y:longint);//合并两集合 var xx,yy:longint; begin xx:=getfather(x); yy:=getfather(y); father[xx]:=yy; end; function judge(x,y:longint):boolean;//判断是否在一集合中 var xx,yy:longint; begin xx:=getfather(x); yy:=getfather(y); exit(xx=yy); end; begin readln(n,m,p); for i:=1 to n do father[i]:=i; for i:=1 to m do begin readln(j,k); merge(j,k); end; for i:=1 to p do begin readln(j,k); if judge(j,k) then writeln('Yes') else writeln('No'); end; end.
二分快速幂
var t,a,b,ans:qword; begin readln(a,b); t:=a; ans:=1; while b>0 do begin if odd(b) then ans:=ans*t; t:=t*t; b:=b div 2; end; writeln(ans); end.
线段树
type node=^rec; rec=record l,r,sum,delta:int64; lc,rc:node; end; var root:node; l,r,add,i,n,m,tmp:longint; procedure build(now:node;l,r:longint); begin now^.l:=l;now^.r:=r; if l=r then begin read(now^.sum); now^.lc:=nil; now^.rc:=nil; exit; end; new(now^.lc); new(now^.rc); build(now^.lc,l,(l+r)div 2); build(now^.rc,(l+r)div 2+1,r); now^.sum:=now^.lc^.sum+now^.rc^.sum; end; procedure update(now:node;l,r,add:int64); begin if (l<=now^.l)and(now^.r<=r) then begin inc(now^.delta,add); exit; end; if l<=(now^.l+now^.r)div 2 then update(now^.lc,l,r,add); if r>(now^.l+now^.r)div 2 then update(now^.rc,l,r,add); now^.sum:=now^.lc^.sum+now^.lc^.delta*(now^.lc^.r-now^.lc^.l+1); inc(now^.sum,now^.rc^.sum+now^.rc^.delta*(now^.rc^.r-now^.rc^.l+1)); end; function query(now:node;l,r:longint):int64; var ret:int64; begin if (l<=now^.l)and(now^.r<=r) then exit(now^.sum+now^.delta*(now^.r-now^.l+1)); inc(now^.lc^.delta,now^.delta); inc(now^.rc^.delta,now^.delta); inc(now^.sum,now^.delta*(now^.r-now^.l+1)); now^.delta:=0; ret:=0; if l<=(now^.l+now^.r)div 2 then inc(ret,query(now^.lc,l,r)); if r>(now^.l+now^.r)div 2 then inc(ret,query(now^.rc,l,r)); exit(ret); end; begin new(root); readln(n); build(root,1,n); readln(m); for i:=1 to m do begin read(tmp); if tmp=1 then begin readln(l,r,add); update(root,l,r,add); end; if tmp=2 then begin readln(l,r); writeln(query(root,l,r)); end; end; end.
SPFA
const maxp=1000; var p,c,s,t,head,tail:longint; a,b:array[0..maxp,0..maxp] of longint; d:array[0..maxp] of integer; v:array[0..maxp] of boolean; dist:array[0..maxp] of longint; procedure init; var i,x,y,z:longint; begin readln(p,c); for i:=1 to c do begin readln(x,y,z); inc(b[x,0]); b[x,b[x,0]] := y; a[x,y] :=z; end; readln(s,t); end; procedure spfa(s:longint); var i,j,now,sum:longint; begin fillchar(d,sizeof(d),0); fillchar(v,sizeof(v),false); for j:=1 to p do dist[j]:=maxlongint; dist[s]:=0;v[s]:=true;d[1]:=s; head:=1;tail:=1; while head<=tail do begin now:=d[head]; for i:=1 to b[now,0] do if dist[b[now,i]]>dist[now]+a[now,b[now,i]] then begin dist[b[now,i]]:= dist[now]+a[now,b[now,i]]; if not v[b[now,i]] then begin inc(tail); d[tail]:=b[now,i]; v[b[now,i]]:=true; end; end;inc(head); v[now]:=false; end; end; begin init; spfa(s); writeln(dist[t]); end. type point=^rec; rec=record sum:longint; data:integer; next:point; end; var i,n,m:longint; dist:array[0..10000]of longint; h:array[1..20000]of integer; v:array[1..10000]of boolean; a:array[0..10000]of point; procedure init; var i,z:longint; x,y:integer; k:point; begin read(n,m); for i:=1 to m do begin new(k); readln(x,y,z); k^.data:=y; k^.sum:=z; k^.next:=a[x]; a[x]:=k; end; end; procedure spfa(x:longint); var front,rear,now,j:longint; i:point; begin for j:=1 to n do dist[j]:=maxlongint; dist[x]:=0;front:=0;rear:=1;h[1]:=x;v[x]:=true; while front<rear do begin inc(front); now:=h[front]; i:=a[now]; while i<>nil do begin if dist[i^.data]>dist[now]+i^.sum then begin dist[i^.data]:=dist[now]+i^.sum; if not v[i^.data] then begin inc(rear); h[rear]:=i^.data; v[i^.data]:=true; end; end; i:=i^.next; end; v[now]:=false; end; end; begin init; spfa(1); writeln(dist[n]); end. var i,p,c,s,t:longint; a,b:array[0..1000,0..1000]of longint; v:array[0..1000] of boolean; q,dist:array[0..1000] of longint; procedure init; var x,y,z:longint; begin fillchar(b,sizeof(b),0); readln(p,c); readln(s,t); for i:=1 to c do begin readln(x,y,z); inc(b[x,0]);b[x,b[x,0]]:=y; a[x,y]:=z; end; end; procedure spfa; var head,tail,now:longint; begin head:=1; tail:=1; fillchar(v,sizeof(v),false); for i:=1 to p do dist[i]:=maxlongint; q[1]:=p;v[p]:=true;dist[p]:=0; while head<=tail do begin now:=q[head]; for i:=1 to b[now,0] do begin if dist[b[now,i]]>dist[now]+a[now,b[now,i]] then begin dist[b[now,i]]:=dist[now]+a[now,b[now,i]]; if not v[b[now,i]] then begin v[b[now,i]]:=true; inc(tail); q[tail]:=b[now,i]; end; end; end; inc(head);v[now]:=false; end; end; begin init; spfa; writeln(dist[t]); end.
