好像要1A模板题。完败

下面主要是一波SB错误总结

最小生成树（忘了sort（QwQ））

// It is made by XZZ

// Fei Fan Ya Xi Lie~~~

#include<cstdio>

#include<algorithm>

using namespace std;

#define il inline

#define rg register

#define vd void

typedef long long ll;

il int gi(){

    rg int x=0,f=1;rg char ch=getchar();

    while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();

    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();

    return x*f;

}

struct frog{int a,b,c;}p[200001];

il bool operator <(const frog&a,const frog&b){return a.c<b.c;}

int fa[5001];

il int hd(const int&a){return a==fa[a]?a:fa[a]=hd(fa[a]);}

int main(){

// 	freopen("3366.in","r",stdin);

// 	freopen("3366.out","w",stdout);

    int n=gi(),m=gi()+1;

    for(rg int i=1;i<m;++i)p[i].a=gi(),p[i].b=gi(),p[i].c=gi();

    sort(p+1,p+m+1);

    for(rg int i=1;i<=n;++i)fa[i]=i;

    int orz=1;long long ans=0;

    for(rg int i=1;i<n;++i){

        while((orz^m)&&hd(p[orz].a)==hd(p[orz].b))++orz;

        if(orz==m){puts("orz");return 0;}

        fa[hd(p[orz].b)]=hd(p[orz].a);

        ans+=p[orz].c;

    }

    printf("%lld\n",ans);

    return 0;

}

SB并查集（按秩合并应该不会卡）

// It is made by XZZ

// Fei Fan Ya Xi Lie~~~

#include<cstdio>

#include<algorithm>

using namespace std;

#define il inline

#define rg register

#define vd void

typedef long long ll;

il int gi(){

    rg int x=0,f=1;rg char ch=getchar();

    while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();

    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();

    return x*f;

}

int fa[10001];

il int hd(const int&a){return a==fa[a]?a:fa[a]=hd(fa[a]);}

int main(){

// 	freopen("3367.in","r",stdin);

// 	freopen("3367.out","w",stdout);

    int n=gi(),m=gi(),opt,x,y;

    for(rg int i=1;i<=n;++i)fa[i]=i;

    while(m--){

        opt=gi(),x=gi(),y=gi();

        if(opt==1)fa[hd(x)]=hd(y);

        else printf("%c\n","NY"[hd(x)==hd(y)]);

    }

    return 0;

}

字符串哈希

用set维护即可。防冲突用了pair，防T用了一个自然溢

// It is made by XZZ

// Fei Fan Ya Xi Lie~~~

#include<cstdio>

#include<algorithm>

#include<set>

#include<cstring>

using namespace std;

#define il inline

#define rg register

#define vd void

typedef long long ll;

il int gi(){

    rg int x=0,f=1;rg char ch=getchar();

    while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();

    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();

    return x*f;

}

char str[233333];

set<pair<long long,unsigned> >st;

int main(){

// 	freopen("3370.in","r",stdin);

// 	freopen("3370.out","w",stdout);

    int n=gi(),ans=0,len;

    long long A,bs;unsigned B,BS;

    while(n--){

        scanf("%s",str+1),len=strlen(str+1);

        A=0,B=0;bs=BS=1;

        for(rg int i=1;i<=len;++i){

            A=(A+bs*str[i])%998244353;

            B+=BS*str[i];

            bs=bs*19260817%998244353;

            BS*=2333;

        }

        #ifdef xzz

        printf("%s %lld %u\n",str+1,A,B);

        #endif

        if(st.find(make_pair(A,B))==st.end())++ans,st.insert(make_pair(A,B));

    }

    printf("%d\n",ans);

    return 0;

}

单源最短路

似乎是常数较小的spfa。dij懒得写了

// It is made by XZZ

// Fei Fan Ya Xi Lie~~~

#include<cstdio>

#include<algorithm>

#include<set>

#include<cstring>

using namespace std;

#define il inline

#define rg register

#define vd void

typedef long long ll;

il int gi(){

    rg int x=0,f=1;rg char ch=getchar();

    while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();

    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();

    return x*f;

}

const int maxn=10001,maxm=500001;

int fir[maxn],dis[maxm],nxt[maxm],w[maxm],id;

il vd add(const int&a,const int&b,const int&c){nxt[++id]=fir[a],fir[a]=id,dis[id]=b,w[id]=c;}

il vd SPFA(long long*dist,int S){

    static int que[maxn],hd,tl,x;

    static bool inque[maxn]={0};

    hd=tl=0;que[tl++]=S;inque[S]=1;

    dist[S]=0;

    while(hd^tl){

        x=que[hd];

        for(rg int i=fir[x];i;i=nxt[i])

            if(dist[dis[i]]>dist[x]+w[i]){

                dist[dis[i]]=dist[x]+w[i];

                if(!inque[dis[i]]){

                    inque[dis[i]]=1;

                    que[tl++]=dis[i];

                    if(tl==maxn)tl=0;

                }

            }

        ++hd;if(hd==maxn)hd=0;

        inque[x]=0;

    }

}

int main(){

// 	freopen("3371.in","r",stdin);

// 	freopen("3371.out","w",stdout);

    int n=gi(),m=gi(),s=gi(),x,y,z;

    while(m--)x=gi(),y=gi(),z=gi(),add(x,y,z);

    static long long dist[maxn];

    for(rg int i=1;i<=n;++i)dist[i]=1e15;

    SPFA(dist,s);

    for(rg int i=1;i<=n;++i){

        if(dist[i]==1e15)dist[i]=2147483647;

        printf("%lld ",dist[i]);

    }

    return 0;

}

缩点+DP

tarjan大家都会了吧。vector存新图

// It is made by XZZ

// Fei Fan Ya Xi Lie~~~

#include<cstdio>

#include<algorithm>

#include<set>

using namespace std;

#define il inline

#define rg register

#define vd void

typedef long long ll;

il int gi(){

    rg int x=0,f=1;rg char ch=getchar();

    while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();

    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();

    return x*f;

}

const int maxn=10001,maxm=100001;

int fir[maxn],dis[maxm],nxt[maxm],id;

il vd add(const int&a,const int&b){nxt[++id]=fir[a],fir[a]=id,dis[id]=b;}

int w[maxn],W[maxn],fr[maxn],top;

int dfn[maxn],low[maxn];

set<int>T[maxn];

int stk[maxn];bool instk[maxn];

il vd tarjan(const int&x){

    dfn[x]=low[x]=++dfn[0];

    stk[++top]=x;instk[x]=1;

    for(int i=fir[x];i;i=nxt[i])

        if(!dfn[dis[i]])tarjan(dis[i]),low[x]=min(low[x],low[dis[i]]);

        else if(instk[dis[i]])low[x]=min(low[x],dfn[dis[i]]);

    if(low[x]==dfn[x]){

        do{

            instk[stk[top]]=0;

            fr[stk[top]]=fr[0];

            W[fr[0]]+=w[stk[top]];

            --top;

        }while(stk[top+1]^x);

        ++fr[0];

    }

}

ll f[maxn];

il ll dp(int x){

    if(f[x])return f[x];

    f[x]=0;

    for(set<int>::iterator it=T[x].begin();it!=T[x].end();++it)

        f[x]=max(f[x],dp(*it));

    f[x]+=W[x];

    return f[x];

}

int main(){

// 	freopen("3387.in","r",stdin);

// 	freopen("3387.out","w",stdout);

    int n=gi()+1,m=gi(),u,v;

    for(rg int i=1;i<n;++i)w[i]=gi();

    while(m--)u=gi(),v=gi(),add(u,v);

    fr[0]=1;

    for(rg int i=1;i<n;++i)if(!dfn[i])tarjan(i);

    for(rg int i=1;i<n;++i)

        for(rg int j=fir[i];j;j=nxt[j])

            if(fr[i]^fr[dis[j]])T[fr[dis[j]]].insert(fr[i]);

    ll ans=0;

    for(rg int i=1;i<fr[0];++i)ans=max(ans,dp(i));

    printf("%lld\n",ans);

    return 0;

}

ST表

SB错误犯几次，我还说这是我打的最熟的东西。QwQ

SB错误：预处理log时没想清

    for(rg int i=2;i<n;++i)

        if(1<<log[i-1]+1==i)log[i]=log[i-1]+1;

        else log[i]=log[i-1];

代码：

// It is made by XZZ

// Fei Fan Ya Xi Lie~~~

#include<cstdio>

#include<algorithm>

using namespace std;

#define il inline

#define rg register

#define vd void

typedef long long ll;

il int gi(){

    rg int x=0,f=1;rg char ch=getchar();

    while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();

    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();

    return x*f;

}

int st[17][100001];

int log[100001];

int main(){

// 	freopen("3865.in","r",stdin);

// 	freopen("3865.out","w",stdout);

    int n=gi()+1,m=gi(),Log;

    for(rg int i=2;i<n;++i)

        if(1<<log[i-1]+1==i)log[i]=log[i-1]+1;

        else log[i]=log[i-1];

    for(rg int i=1;i<n;++i)st[0][i]=gi();

    Log=log[n-1]+1;

    for(rg int i=1;i<Log;++i)

        for(rg int j=n-(1<<i)+1;j;--j)

            st[i][j]=max(st[i-1][j],st[i-1][j+(1<<(i-1))]);

    int l,r,lg;

    while(m--){

        l=gi(),r=gi(),lg=log[r-l+1];

        printf("%d\n",max(st[lg][l],st[lg][r-(1<<lg)+1]));

    }

    return 0;

}

LCA

这个不1A我真是SB了。

// It is made by XZZ

// Fei Fan Ya Xi Lie~~~

#include<cstdio>

#include<algorithm>

#include<cmath>

using namespace std;

#define il inline

#define rg register

#define vd void

typedef long long ll;

il int gi(){

    rg int x=0,f=1;rg char ch=getchar();

    while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();

    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();

    return x*f;

}

int st[19][500001],_log,n,m,rt;

const int maxn=500001,maxm=1000001;

int fir[maxn],dis[maxm],nxt[maxm],dep[maxn],id;

il vd add(const int&a,const int&b){nxt[++id]=fir[a],fir[a]=id,dis[id]=b;}

il vd dfs(const int&x){

    for(rg int i=fir[x];i;i=nxt[i])

        if(dis[i]^st[0][x])st[0][dis[i]]=x,dep[dis[i]]=dep[x]+1,dfs(dis[i]);

}

il int LCA(int a,int b){

    if(dep[a]<dep[b])swap(a,b);

    for(rg int i=_log;~i;--i)if(dep[st[i][a]]>dep[b])a=st[i][a];

    if(dep[a]^dep[b])a=st[0][a];

    for(rg int i=_log;~i;--i)if(st[i][a]^st[i][b])a=st[i][a],b=st[i][b];

    if(a^b)a=st[0][a];

    return a;

}

int main(){

// 	freopen("lca.in","r",stdin);

// 	freopen("lca.out","w",stdout);

    n=gi(),m=gi(),rt=gi();

    int u,v;

    for(rg int i=1;i<n;++i)u=gi(),v=gi(),add(u,v),add(v,u);

    _log=log2(n);

    dfs(rt);

    for(rg int i=1;i<=_log;++i)

        for(rg int j=1;j<=n;++j)

            st[i][j]=st[i-1][st[i-1][j]];

    while(m--)printf("%d\n",LCA(gi(),gi()));

    return 0;

}

线性筛

才发现不会，来学一下。

大概是每个合数用最大的那个因子筛掉。

要加if(i%prime[j]==0)break剪枝。

总复习再看一轮吧（肯定理解不了辣 背背板子吧QwQ）

// It is made by XZZ

// Fei Fan Ya Xi Lie~~~

#include<cstdio>

#include<algorithm>

using namespace std;

#define il inline

#define rg register

#define vd void

typedef long long ll;

il int gi(){

    rg int x=0,f=1;rg char ch=getchar();

    while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();

    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();

    return x*f;

}

bool yes[10000001];

int prime[2333333];

const char out[][233]={"Yes","No"};

int main(){

// 	freopen("3383.in","r",stdin);

// 	freopen("3383.out","w",stdout);

    int n=gi()+1,m=gi();

    yes[0]=yes[1]=1;

    prime[0]=1;

    for(rg int i=2;i<n;++i){

        if(yes[i]==0)prime[prime[0]++]=i;

        for(rg int j=1;j<prime[0]&&i*prime[j]<n;++j){

            yes[i*prime[j]]=1;

            if(i/prime[j]*prime[j]==i)break;

        }

    }

    while(m--)puts(out[yes[gi()]]);

    return 0;

}

割点

洛谷数据有bug，用的城市的备用交换机

// It is made by XZZ

// Fei Fan Ya Xi Lie~~~

#include<cstdio>

#include<algorithm>

using namespace std;

#define il inline

#define rg register

#define vd void

typedef long long ll;

il int gi(){

	rg int x=0,f=1;rg char ch=getchar();

	while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();

	while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();

	return x*f;

}

const int maxn=100010,maxm=maxn<<1;

int fir[maxn],nxt[maxm],dis[maxm],id;

il vd add(const int&a,const int&b){nxt[++id]=fir[a],fir[a]=id,dis[id]=b;}

bool yes[maxn];

int dfn[maxn],low[maxn];

int cnt=0;

il vd tarjan(const int&x){

	dfn[x]=low[x]=++dfn[0];

	for(int i=fir[x];i;i=nxt[i])

		if(!dfn[dis[i]]){

			tarjan(dis[i]),low[x]=min(low[x],low[dis[i]]);

			if(low[dis[i]]>=dfn[x]){

				if(x==1)++cnt;

				else yes[x]=1;

			}

		}

		else low[x]=min(low[x],dfn[dis[i]]);

	if(x==1)yes[x]=cnt>1;

}

int main(){

// 	freopen("3388.in","r",stdin);

// 	freopen("3388.out","w",stdout);

	int n=gi(),u,v;

	while(scanf("%d%d",&u,&v)==2)add(u,v),add(v,u);

	tarjan(1);

	int tot=0;

	for(rg int i=1;i<=n;++i)if(yes[i])++tot;

	printf("%d\n",tot);

	for(rg int i=1;i<=n;++i)if(yes[i])printf("%d\n",i);

	return 0;

}