行列式

#include<iostream>
#include<cstdio>
#define maxn 500010
using namespace std;
int n,m,mod,l,r,x,y,b[maxn],a[maxn],cnt;
void dfs(int now[],int sz){
    if(sz<=2){
        for(int i=1;i<=sz;i++)b[++cnt]=now[i];
        return;
    }
    int sz1=0,sz2=0;
    int d[sz],c[sz];
    
 
for(int i=1;i<=sz;i++){
        if(i%2!=0){//奇數位 
            c[++sz1]=now[i]; 
        }
        if(i%2==0){//偶數位 
            d[++sz2]=now[i];
        }
    }
    dfs(c,sz1);
    dfs(d,sz2);
}
int main(){
    //freopen("Cola.txt","r",stdin);
    freopen("seq.in","r",stdin);freopen("seq.out
 
","w",stdout);
    scanf("%d%d%d",&n,&m,&mod);
    for(int i=1;i<=n;i++)a[i]=i;
    dfs(a,n);
    long long ans;
    for(int i=1;i<=m;i++){
        scanf("%d%d%d%d",&l,&r,&x,&y);
        ans=0;
        if(x>y)swap(x,y);
        for(int j=l;j<=r;j++){
            
 
if(b[j]<=y&&b[j]>=x){
                ans=(ans+b[j])%mod;
            }
        }printf("%I64d\n",ans);
    }
    fclose(stdin);fclose(stdout);
    return 0;
}

序列

數數

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
#define maxn 100010
using namespace std;
int num,head[maxn];
int sz[maxn],son[maxn],fa[maxn],top[maxn],dep[maxn];
long long ans;
struct node{
    int to,pre;
}e[maxn*2];
int n,dis[2010][2010];
bool vis[maxn];
void Insert(int from,int to){
    e[++num].to=to;
    e[num].pre=head[from];
    head[from]=num;
}
void Bfs(int s){
    queue<int>q;
    memset(vis,0,sizeof(vis));
    vis[s]=1;q.push(s);dis[s][s]=0;
    while(!q.empty()){
        int now=q.front();q.pop();
        for(int i=head[now];i;i=e[i].pre){
            int to=e[i].to;
            if(vis[to])continue;
            else {
                dis[s][to]=dis[s][now]+1;
                vis[to]=1;
                q.push(to);
            }
        }
    }
}
int count(int x){
    int res=0;
    while(x){
        res+=x&1;
        x>>=1;
    }
    return res;
}
void dfs1(int now,int father){
    dep[now]=dep[father]+1;
    sz[now]=1;fa[now]=father;
    for(int i=head[now];i;i=e[i].pre){
        int to=e[i].to;
        if(to==father)continue;
        dfs1(to,now);
        sz[now]+=sz[to];
        if(!son[now]||sz[son[now]]<sz[to])son[now]=to;
    }
}
void dfs2(int now,int father){
    top[now]=father;
    if(son[now])dfs2(son[now],father);
    for(int i=head[now];i;i=e[i].pre){
        int to=e[i].to;
        if(to==fa[now]||to==son[now])continue;
        dfs2(to,to);
    }
}
int LCA(int a,int b){
    while(top[a]!=top[b]){
        if(dep[top[a]]<dep[top[b]])swap(a,b);
        a=fa[top[a]];
    }
    if(dep[a]>dep[b])swap(a,b);
    return a;
}
int main(){
    //freopen("Cola.txt","r",stdin);
    freopen("bitcount.in","r",stdin);freopen("bitcount.out","w",stdout);
    scanf("%d",&n);
    int x,y;
    for(int i=1;i<n;i++){
        scanf("%d%d",&x,&y);
        Insert(x,y);Insert(y,x);
    }
    for(int i=1;i<=n;i++)Bfs(i);
    for(int i=1;i<=n;i++)
        for(int j=1;j<=n;j++)
            dis[i][j]=count(dis[i][j]);
    dfs1(1,0);
    dfs2(1,1);
    for(int i=1;i<=n;i++){
        for(int j=i+1;j<=n;j++){
            int lca=LCA(i,j);
            ans+=dis[i][lca]+dis[j][lca];
        }
    }
    cout<<ans;
    fclose(stdin);fclose(stdout);
    return 0;
}

2017-10-5 清北刷題沖刺班a.m