临阵磨枪——CSP-S板子小总结
倍增lca(BY_ahawzlc)(P3379)
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<stack>
#include<cmath>
#include<queue>
#include<set>
#include<map>
#define re register
#define pi pair<int,int>
#define F first
#define S second
using namespace std;
const int N=500005;
inline int read() {
int sum=0,w=1;
char ch=getchar();
while(ch<'0'||ch>'9') {
if(ch=='-') w=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9') {
sum=(sum<<3)+(sum<<1)+ch-'0';
ch=getchar();
}
return sum*w;
}
int cnt,nxt[N<<1],to[N<<1],h[N],deep[N],p[N][20],n,m,s;
void add(int x,int y) {
nxt[++cnt]=h[x];
to[cnt]=y;
h[x]=cnt;
}
int lca(int a,int b) {
int dep;
if(deep[a]<deep[b]) swap(a,b);
for(dep=0;(1<<dep)<=deep[a];dep++);
dep--;
for(int i=dep;i>=0;i--) if(deep[a]-(1<<i)>=deep[b]) a=p[a][i];
if(a==b) return a;
for(int i=dep;i>=0;i--) if(p[a][i]!=-1&&p[a][i]!=p[b][i]) a=p[a][i],b=p[b][i];
return p[a][0];
}
void dfs(int x) {
for(int i=h[x];i;i=nxt[i]) {
int y=to[i];
if(!deep[y]&&y!=s) {
deep[y]=deep[x]+1;
p[y][0]=x;
dfs(y);
}
}
}
void init(int s) {
memset(p,-1,sizeof p);
memset(deep,0,sizeof deep);
dfs(s);
for(int j=0;(1<<j)<=n;j++)
for(int i=1;i<=n;i++) if(p[i][j-1]!=-1) p[i][j]=p[p[i][j-1]][j-1];
}
int main() {
n=read(),m=read(),s=read();
for(int i=1;i<n;i++) {
int x=read(),y=read();
add(x,y),add(y,x);
}
init(s);
while(m--) {
int x=read(),y=read(),ans;
ans=lca(x,y);
printf("%d\n",ans);
}
return 0;
}
树剖(BY_ahawzlc)(P3384)
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<stack>
#include<cmath>
#include<queue>
#include<set>
#include<map>
#define re register
#define pi pair<int,int>
#define F first
#define S second
#define mid ((l+r)>>1)
#define lson (now<<1)
#define rson (now<<1|1)
using namespace std;
const int N=200005;
inline int read() {
int sum=0,w=1;
char ch=getchar();
while(ch<'0'||ch>'9') {
if(ch=='-') w=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9') {
sum=(sum<<3)+(sum<<1)+ch-'0';
ch=getchar();
}
return sum*w;
}
int n,m,mod,r,cnt,nxt[N<<1],to[N<<1],h[N];
void add(int x,int y) {
to[++cnt]=y;
nxt[cnt]=h[x];
h[x]=cnt;
}
int tree[N*5],lazy[N*5],va[N];
void update(int now) {
tree[now]=(tree[lson]+tree[rson])%mod;
}
void pushdown(int now,int l,int r) {
if(lazy[now]) {
lazy[lson]+=lazy[now];
lazy[rson]+=lazy[now];
tree[lson]=(tree[lson]+lazy[now]*(mid-l+1))%mod;
tree[rson]=(tree[rson]+lazy[now]*(r-mid))%mod;
lazy[now]=0;
}
}
void build(int now,int l,int r) {
if(l==r) {tree[now]=va[l];return;}
build(lson,l,mid);
build(rson,mid+1,r);
update(now);
}
void change(int now,int l,int r,int x,int y,int z) {
if(x<=l&&r<=y) {lazy[now]+=z;tree[now]=(tree[now]+z*(r-l+1))%mod;return;}
pushdown(now,l,r);
if(x<=mid) change(lson,l,mid,x,y,z);
if(y>mid) change(rson,mid+1,r,x,y,z);
update(now);
}
int que=0;
void ask(int now,int l,int r,int x,int y) {
if(x<=l&&r<=y) {que=(que+tree[now])%mod;return;}
pushdown(now,l,r);
if(x<=mid) ask(lson,l,mid,x,y);
if(y>mid) ask(rson,mid+1,r,x,y);
}
int nn,dep[N],id[N],siz[N],ver[N],fa[N],w[N],top[N];
void dfs1(int x,int f,int d) {
dep[x]=d;
fa[x]=f;
siz[x]=1;
int ms=-1;
for(int i=h[x];i;i=nxt[i]) {
int y=to[i];
if(y==f) continue;
dfs1(y,x,d+1);
siz[x]+=siz[y];
if(siz[y]>ms) ms=siz[y],ver[x]=y;
}
}
void dfs2(int x,int topf) {
top[x]=topf;
id[x]=++nn;
va[nn]=w[x];
if(!ver[x]) return;
dfs2(ver[x],topf);
for(int i=h[x];i;i=nxt[i]) {
int y=to[i];
if(y==fa[x]||y==ver[x]) continue;
dfs2(y,y);
}
}
void addr(int x,int y,int z) {
z%=mod;
while(top[x]!=top[y]) {
if(dep[top[x]]<dep[top[y]])
swap(x,y);
change(1,1,n,id[top[x]],id[x],z);
x=fa[top[x]];
}
if(dep[x]>dep[y])
swap(x,y);
change(1,1,n,id[x],id[y],z);
}
void adds(int x,int z) {
change(1,1,n,id[x],id[x]+siz[x]-1,z);
}
int queryr(int x,int y) {
int ans=0;
while(top[x]!=top[y]) {
if(dep[top[x]]<dep[top[y]])
swap(x,y);
que=0;
ask(1,1,n,id[top[x]],id[x]);
ans=(ans+que)%mod;
x=fa[top[x]];
}
if(dep[x]>dep[y])
swap(x,y);
que=0;
ask(1,1,n,id[x],id[y]);
ans=(ans+que)%mod;
return ans;
}
int querys(int x) {
que=0;
ask(1,1,n,id[x],id[x]+siz[x]-1);
return que;
}
int main() {
int r;
n=read(),m=read(),r=read(),mod=read();
for(int i=1;i<=n;i++) w[i]=read();
for(int i=1;i<n;i++) {
int a=read(),b=read();
add(a,b),add(b,a);
}
dfs1(r,0,1);
dfs2(r,r);
build(1,1,n);
while(m--) {
int opt=read(),x=read(),y,z;
if(opt==1) {
y=read(),z=read();
addr(x,y,z);
}
if(opt==2) {
y=read();
printf("%d\n",queryr(x,y));
}
if(opt==3) {
y=read();
adds(x,y);
}
if(opt==4)
printf("%d\n",querys(x));
}
return 0;
}
高精加乘——不考虑负数(BY_ahawzlc)(P1303/P1601)
#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
#include<vector>
#include<queue>
#include<set>
#include<map>
const int N=100005;
using namespace std;
inline int read() {
int sum=0,w=1;
char ch=getchar();
while(ch<'0'||ch>'9') {
if(ch=='-') w=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9') {
sum=(sum<<3)+(sum<<1)+(ch-'0');
ch=getchar();
}
return sum*w;
}
int numa[N],numb[N],numc[N];
char c[N],aa[N],bb[N];
void muti(const char *a,const char *b) {
int lena=strlen(a),lenb=strlen(b);
memset(c,0,sizeof c);
memset(numc,0,sizeof numc);
for(int i=1;i<=lena;++i) numa[i]=a[lena-i]-'0';
for(int i=1;i<=lenb;++i) numb[i]=b[lenb-i]-'0';
for(int i=1;i<=lena;i++) for(int j=1;j<=lenb;j++) numc[i+j-1]+=numa[i]*numb[j];
int len=lena+lenb;
for(int i=1;i<len;i++) if(numc[i]>9) {
numc[i+1]+=numc[i]/10;numc[i]%=10;
}
while(numc[len]==0&&len>1) len--;
for(int i=len;i>=1;i--) c[len-i]=numc[i]+'0';
}
void pl(const char *a,const char *b) {
int lena=strlen(a),lenb=strlen(b);
memset(c,0,sizeof c);
memset(numc,0,sizeof numc);
for(int i=1;i<=lena;++i) numa[i]=a[lena-i]-'0';
for(int i=1;i<=lenb;++i) numb[i]=b[lenb-i]-'0';
int len=max(lena,lenb);
for(int i=1;i<=len;i++) numc[i]=numa[i]+numb[i];
for(int i=1;i<=len;i++) if(numc[i]>9) {
numc[i+1]+=numc[i]/10;numc[i]%=10;
}
len++;
while(numc[len]==0&&len>1) len--;
for(int i=len;i>=1;i--) c[len-i]=numc[i]+'0';
}
int main() {
/*cin>>aa>>bb;
pl(aa,bb);
cout<<c;*/
cin>>aa>>bb;
muti(aa,bb);
cout<<c;
return 0;
}
dijkstra(djh123)(BY_ahawzlc)(P4779)
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<stack>
#include<cmath>
#include<queue>
#include<set>
#include<map>
#define re register
#define pi pair<int,int>
#define F first
#define S second
#define mp make_pair
using namespace std;
const int N=200005;
inline int read() {
int sum=0,w=1;
char ch=getchar();
while(ch<'0'||ch>'9') {
if(ch=='-') w=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9') {
sum=(sum<<3)+(sum<<1)+ch-'0';
ch=getchar();
}
return sum*w;
}
int cnt,nxt[N],to[N],h[N],cost[N],dis[N],n,m,s;
priority_queue<pi> q;
bool vis[N];
void add(int x,int y,int z) {
nxt[++cnt]=h[x];
cost[cnt]=z;
to[cnt]=y;
h[x]=cnt;
}
void djh123(int s) {
memset(dis,0x3f,sizeof dis);
memset(vis,0,sizeof vis);
while(q.size()) q.pop();
q.push(mp(0,s));
dis[s]=0;
while(q.size()) {
int u=q.top().S;
q.pop();
if(vis[u]) continue;
vis[u]=1;
for(int i=h[u];i;i=nxt[i]) {
int v=to[i];
if(dis[u]+cost[i]<dis[v]) {
dis[v]=dis[u]+cost[i];
q.push(mp(-dis[v],v));
}
}
}
}
int main() {
n=read(),m=read(),s=read();
for(int i=1;i<=m;i++) {
int x=read(),y=read(),z=read();
add(x,y,z);
}
djh123(s);
for(int i=1;i<=n;i++) printf("%d ",dis[i]);
return 0;
}
Tarjan割点、强连通分量(施公算法)(BY_ahawzlc)(P3388)
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<stack>
#include<cmath>
#include<queue>
#include<set>
#include<map>
#define re register
#define pi pair<int,int>
#define F first
#define S second
using namespace std;
const int N=200005;
inline int read() {
int sum=0,w=1;
char ch=getchar();
while(ch<'0'||ch>'9') {
if(ch=='-') w=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9') {
sum=(sum<<3)+(sum<<1)+ch-'0';
ch=getchar();
}
return sum*w;
}
int n,m,h[N],cnt,nxt[N],to[N];
void add(int x,int y) {
nxt[++cnt]=h[x];
to[cnt]=y;
h[x]=cnt;
}
int id,dfn[N],low[N],root,tot;
stack<int> s;
bool cut[N];
/*bool vis[N];
int siz[N],bl[N];
void tarjan(int u) {
dfn[u]=low[u]=++id;
s.push(u);
vis[u]=1;
for(int i=h[u];i;i=nxt[i]) {
int v=to[i];
if(!dfn[v]) {
tarjan(v);
low[u]=min(low[u],low[v]);
} else if(vis[v]) low[u]=min(low[u],dfn[v]);
}
if(dfn[u]==low[u]) {
int v;
tarn++;
do {
v=s.top();
s.pop();
bl[v]=tarn;
siz[tarn]++;
vis[v]=0;
} while(v!=u);
}
}*/
void tarjan(int u) {
dfn[u]=low[u]=++id;
int flag=0;
for(int i=h[u];i;i=nxt[i]) {
int v=to[i];
if(!dfn[v]) {
tarjan(v);
low[u]=min(low[u],low[v]);
if(low[v]>=dfn[u]) {
flag++;
if(u!=root||flag>1) cut[u]=1;
}
} else low[u]=min(low[u],dfn[v]);
}
}
int main() {
int n=read(),m=read();
for(int i=1;i<=m;i++) {
int x=read(),y=read();
if(x==y) continue;
add(x,y),add(y,x);
}
for(int i=1;i<=n;i++) if(!dfn[i]) root=i,tarjan(i);
for(int i=1;i<=n;i++) if(cut[i]) tot++;
printf("%d\n",tot);
for(int i=1;i<=n;i++) if(cut[i]) printf("%d ",i);
return 0;
}
负环SPFA(BY_ahawzlc)(P3385)
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<stack>
#include<cmath>
#include<queue>
#include<set>
#include<map>
#define re register
#define pi pair<int,int>
#define F first
#define S second
using namespace std;
const int N=200005;
inline int read() {
int sum=0,w=1;
char ch=getchar();
while(ch<'0'||ch>'9') {
if(ch=='-') w=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9') {
sum=(sum<<3)+(sum<<1)+ch-'0';
ch=getchar();
}
return sum*w;
}
int cnt,h[N],nxt[N*3],to[N*3],cost[N*3],tot[N],dis[N],n,m;
void add(int x,int y,int z) {
nxt[++cnt]=h[x];
to[cnt]=y;
cost[cnt]=z;
h[x]=cnt;
}
queue<int> q;
bool vis[N];
bool spfa(int s) {
memset(dis,0x3f,sizeof dis);
memset(vis,0,sizeof vis);
memset(tot,0,sizeof tot);
while(q.size()) q.pop();
dis[s]=0,vis[s]=1;
q.push(s);
while(q.size()) {
int u=q.front();
q.pop();
vis[u]=0;
for(int i=h[u];i;i=nxt[i]) {
int v=to[i],c=cost[i];
if(dis[v]>dis[u]+c) {
dis[v]=dis[u]+c;
tot[v]=tot[u]+1;
if(tot[v]>=n) return 1;
if(!vis[v]) {
q.push(v);
vis[v]=1;
}
}
}
}
return 0;
}
int main() {
int t=read();
while(t--) {
memset(h,0,sizeof h);
memset(nxt,0,sizeof nxt);
memset(cost,0,sizeof cost);
memset(to,0,sizeof to);
cnt=0;
n=read(),m=read();
while(m--) {
int x=read(),y=read(),z=read();
add(x,y,z);
if(z>=0) add(y,x,z);
}
if(spfa(1)) puts("YES");
else puts("NO");
}
return 0;
}
KMP(BY_ahawzlc)(P3375)
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<stack>
#include<cmath>
#include<queue>
#include<set>
#include<map>
#define re register
#define pi pair<int,int>
#define F first
#define S second
using namespace std;
const int N=1000006;
inline int read() {
int sum=0,w=1;
char ch=getchar();
while(ch<'0'||ch>'9') {
if(ch=='-') w=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9') {
sum=(sum<<3)+(sum<<1)+ch-'0';
ch=getchar();
}
return sum*w;
}
char a[N],b[N];
int kmp[N],lena,lenb,now;
int main() {
scanf("%s",a+1);
scanf("%s",b+1);
lena=strlen(a+1),lenb=strlen(b+1);
for(int i=2;i<=lenb;i++) {
while(now&&b[i]!=b[now+1]) now=kmp[now];
if(b[now+1]==b[i]) now++;
kmp[i]=now;
}
now=0;
for(int i=1;i<=lena;i++) {
while(now>0&&b[now+1]!=a[i]) now=kmp[now];
if(b[now+1]==a[i]) now++;
if(now==lenb) printf("%d\n",i-lenb+1),now=kmp[now];
}
for(int i=1;i<=lenb;i++) printf("%d ",kmp[i]);
return 0;
}
AC自动机(BY_ahawzlc)(P3796)
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<stack>
#include<cmath>
#include<queue>
#include<set>
#include<map>
#define re register
#define pi pair<int,int>
#define F first
#define S second
using namespace std;
const int N=2000005;
inline int read() {
int sum=0,w=1;
char ch=getchar();
while(ch<'0'||ch>'9') {
if(ch=='-') w=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9') {
sum=(sum<<3)+(sum<<1)+ch-'0';
ch=getchar();
}
return sum*w;
}
char s[N];
struct trie {
int fail,vis[26],end;
}ac[N];
int tot;
void build(const char *s) {
int len=strlen(s),now=0,c;
for(int i=0;i<len;i++) {
c=s[i]-'a';
if(ac[now].vis[c]==0) ac[now].vis[c]=++tot;
now=ac[now].vis[c];
}
ac[now].end++;
}
queue<int> q;
void get_fail() {
while(q.size()) q.pop();
for(int i=0;i<26;i++) {
if(ac[0].vis[i]!=0) {
ac[ac[0].vis[i]].fail=0;
q.push(ac[0].vis[i]);
}
}
while(q.size()) {
int u=q.front();
q.pop();
for(int i=0;i<26;i++) {
if(ac[u].vis[i]!=0) {
ac[ac[u].vis[i]].fail=ac[ac[u].fail].vis[i];
q.push(ac[u].vis[i]);
} else ac[u].vis[i]=ac[ac[u].fail].vis[i];
}
}
}
int ask(const char *s) {
int len=strlen(s),now=0,ans=0,c;
for(int i=0;i<len;i++) {
c=s[i]-'a';
now=ac[now].vis[c];
for(int j=now;j&&ac[j].end!=-1;j=ac[j].fail) {
ans+=ac[j].end;
ac[j].end=-1;
}
}
return ans;
}
int main() {
int n=read();
for(int i=1;i<=n;i++) {
scanf("%s",s);
build(s);
}
ac[0].fail=0;
get_fail();
scanf("%s",s);
printf("%d",ask(s));
return 0;
}
最小生成树(BY_ahawzlc)(P3366)
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<stack>
#include<cmath>
#include<queue>
#include<set>
#include<map>
#define re register
#define pi pair<int,int>
#define F first
#define S second
using namespace std;
const int N=200005;
inline int read() {
int sum=0,w=1;
char ch=getchar();
while(ch<'0'||ch>'9') {
if(ch=='-') w=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9') {
sum=(sum<<3)+(sum<<1)+ch-'0';
ch=getchar();
}
return sum*w;
}
struct node {
int u,v,w;
}b[N];
int fa[N],n,m,tot,ans;
int find(int x) {
return fa[x]==x?x:fa[x]=find(fa[x]);
}
void merge(int x,int y) {
x=find(x),y=find(y);
if(x!=y) fa[x]=y;
}
bool cmp(node a,node b) {
return a.w<b.w;
}
int main() {
n=read(),m=read();
for(int i=1;i<=n;i++) fa[i]=i;
for(int i=1;i<=m;i++) {
int x=read(),y=read(),z=read();
b[i].u=x,b[i].v=y,b[i].w=z;
}
sort(b+1,b+m+1,cmp);
for(int i=1;i<=m;i++) {
int x=b[i].u,y=b[i].v;
if(find(x)!=find(y)) {
tot++;
merge(x,y);
ans+=b[i].w;
}
if(tot==n-1) break;
}
bool ok=0;
for(int i=1;i<=n;i++)
if(fa[i]==i) {
if(ok) {
puts("orz");
return 0;
}
ok=1;
}
printf("%d",ans);
return 0;
}
任何一个伟大的计划，都有一个微不足道的开始
