NOIP 2013 解題報告

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

int n,m,k,x;

long long mul(long long x,long long y,long long mod)
{
    if(y==) return ;
    if(y==) return x%mod;
    long long res;
    res=mul(x,y>>,mod);
    if((y&)!=) return(res+res+x)%mod;
    else return(res+res)%mod;
}
long long powermod(long long a,long long b,long long mod) 
{
    long long base=a,res=;
    while(b!=) 
    {
        if(b&!=) res=mul(res,base,mod);
        base=mul(base,base,mod);
        b>>=;
    }
    return res;
}
int main()
{
    freopen("circle.in","r",stdin);
    freopen("circle.out","w",stdout);
    scanf("%d%d%d%d",&n,&m,&k,&x);
    int ans=(x+mul(m,powermod(,k,n),n))%n;
    printf("%d\n",ans);
    return ;
}

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define MAXN 100010
#define MOD 99999997

struct node
{
    int v,t;
}a[MAXN],b[MAXN];
short int cmp(node x,node y)
{
    return x.v<y.v;
}
int n,c[MAXN],ans=;
int t[MAXN];
int lowbit(int x)
{return x&(-x);}
void Add(int x)
{
    for(int i=x;i<=n;i+=lowbit(i)) 
    ++t[i];
}
int Sum(int x)
{
    int rec=;
    for( ;x;x-=lowbit(x)) 
    rec+=t[x];
    return rec;
} 
int main()
{
    freopen("match.in","r",stdin);
    freopen("match.out","w",stdout);
    scanf("%d",&n);
    for(int i=;i<=n;++i) 
    {scanf("%d",&a[i].v);a[i].t=i;}
    for(int i=;i<=n;++i) 
    {scanf("%d",&b[i].v);b[i].t=i;}
    sort(a+,a+n+,cmp);
    sort(b+,b+n+,cmp);
    for(int i=;i<=n;++i) 
    c[a[i].t]=b[i].t;
    for(int i=n;i>=;i--)
    {
        ans+=Sum(c[i]);
        Add(c[i]);
        ans%=MOD;
    }
    printf("%d\n",ans);
    return ;
}

30分做法

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define inf 0x7fffffff
#define N 10010
#define M 500010

int n,m,q,ne;
int head[N];
struct data
{
    int to,next,v;
}e[M*2];

void add(int u,int v,int w)
{
    ne++,
    e[ne].to=v,
    e[ne].v=w,
    e[ne].next=head[u],
    head[u]=ne;
}
void spfa(int x,int y)
{
    int q[N],dis[N],t=,w=;
    int now,i;
    short int vis[N];
    memset(vis,,sizeof(vis));
    memset(dis,-,sizeof(dis));
    q[0]=x,
    vis[x]=,
    dis[x]=inf;
    while(t!=w)
    {
        now=q[t],t++;
        if(t==n) t=;
        i=head[now];
        while(i)
        {
            if(dis[e[i].to]<min(dis[now],e[i].v))
            {
                dis[e[i].to]=min(dis[now],e[i].v);
                if(!vis[e[i].to])
                {
                    vis[e[i].to]=,
                    q[w]=e[i].to,
                    w++;
                    if(w==n) w=;
                }           
            }
            i=e[i].next;
        }
        vis[now]=;
    }
    printf("%d\n",dis[y]);
}
int main()
{
    freopen("truck.in","r",stdin);
    freopen("truck.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(int i=;i<=m;i++)
    {
        int x,y,z;
        scanf("%d%d%d",&x,&y,&z);
        add(x,y,z);add(y,x,z);
    }
    scanf("%d",&q);
    while(q--)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        spfa(x,y);
    }
    return ;
}

60分做法

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define inf 0x7fffffff
#define N 10010
#define M 500010

int n,m,q,ne;
int head[N],father[N];
struct data1
{
    int x,y,v;
}ed[M];
struct data2
{
    int to,next,v;
}e[M*2];

int find(int x)
{return x==father[x]?father[x]:father[x]=find(father[x]);}
short int cmp(data1 a,data1 b)
{return a.v>b.v;}
void add(int u,int v,int w)
{
    ne++,
    e[ne].to=v,
    e[ne].v=w,
    e[ne].next=head[u],
    head[u]=ne;
}
void spfa(int x,int y)
{
    int q[N],dis[N],t=,w=;
    int now,i;
    short int vis[N];
    memset(vis,,sizeof(vis));
    memset(dis,-,sizeof(dis));
    q[0]=x;
    vis[x]=;
    dis[x]=inf;
    while(t!=w)
    {
        now=q[t],t++;
        if(t==n) t=;
        i=head[now];
        while(i)
        {
            if(dis[e[i].to]<min(dis[now],e[i].v))
            {
                dis[e[i].to]=min(dis[now],e[i].v);
                if(!vis[e[i].to])
                {
                    vis[e[i].to]=,
                    q[w]=e[i].to,
                    w++;
                    if(w==n) w=;
                }           
            }
            i=e[i].next;
        }
        vis[now]=;
    }
    printf("%d\n",dis[y]);
}
int main()
{
    freopen("truck.in","r",stdin);
    freopen("truck.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(int i=;i<=m;++i)
    {scanf("%d%d%d",&ed[i].x,&ed[i].y,&ed[i].v);}
    sort(ed+,ed+m+,cmp);
    for(int i=;i<=n;++i) father[i]=i;
    for(int i=;i<=m;++i)
    {
        int x=ed[i].x,y=ed[i].y,v=ed[i].v;
        if(find(x)!=find(y))
        {
            father[find(x)]=find(y);
            add(x,y,v);add(y,x,v);
        }
    }
    scanf("%d",&q);
    for(int i=;i<=q;++i)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        spfa(x,y);
    }
    return ;
}

#include<algorithm>
#include<cstdio>
#include<cstring>
using namespace std;
#define inf 0x7fffffff
#define N 10010
#define M 50010

int n,m,q,cnt,tot,deep[N],head[N],f[N],fa[N][],d[N][];
short int vis[N];
struct edge
{
    int x,y,v;
}a[M];
struct e
{
    int next,to,v;
}e[M*];

int find(int x)
{return f[x]==x?x:f[x]=find(f[x]);}
bool cmp(edge a,edge b)
{return a.v>b.v;}
void add(int u,int v,int w)
{
    e[++cnt].to=v;
    e[cnt].next=head[u];
    head[u]=cnt;
    e[cnt].v=w;
}
void dfs(int x)
{
    vis[x]=;
    for(int i=;i<=;++i)
    {
        if(deep[x]<(<<i)) break;
        fa[x][i]=fa[fa[x][i-]][i-];
        d[x][i]=min(d[x][i-],d[fa[x][i-]][i-]);
    }
    for(int i=head[x];i;i=e[i].next)
    {
        if(vis[e[i].to]) continue;
        fa[e[i].to][]=x;
        d[e[i].to][]=e[i].v;
        deep[e[i].to]=deep[x]+;
        dfs(e[i].to);
    }
}
int lca(int x,int y)
{
    if(deep[x]<deep[y])swap(x,y);
    int t=deep[x]-deep[y];
    for(int i=;i<=;++i)
    if((<<i)&t) x=fa[x][i];
    for(int i=;i>=;i--)
    {
        if(fa[x][i]!=fa[y][i])
        {x=fa[x][i];y=fa[y][i];}
    }
    if(x==y)return x;
    return fa[x][];
}
int ask(int x,int f)
{
    int ans=inf;
    int t=deep[x]-deep[f];
    for(int i=;i<=;++i)
    {
        if(t&(<<i))
        {
           ans=min(ans,d[x][i]);
           x=fa[x][i];
        }
    }
    return ans;
}
int main()
{
    freopen("truck.in","r",stdin);
    freopen("truck.out","w",stdout);
    memset(d,inf,sizeof(d));
    scanf("%d%d",&n,&m);
    for(int i=;i<=n;++i) f[i]=i;
    for(int i=;i<=m;++i)
    scanf("%d%d%d",&a[i].x,&a[i].y,&a[i].v);
    sort(a+,a+m+,cmp);
    for(int i=;i<=m;++i)
    {
        int x=a[i].x,y=a[i].y;
        int p=find(a[i].x),q=find(a[i].y);
        if(p!=q)
        {
            f[p]=q;
            add(x,y,a[i].v);
            add(y,x,a[i].v);
            tot++;
            if(tot==n-) break;
        }
    }
    for(int i=;i<=n;++i) 
    if(!vis[i]) dfs(i);
    for(scanf("%d",&q);q;--q)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        if(find(x)!=find(y))
        {printf("-1\n");continue;}
        else 
        {
            int t=lca(x,y);
            printf("%d\n",min(ask(x,t),ask(y,t)));
        }
    }
    return ;
}

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

int n,x1=,x2=;
long long ans=;

int main()
{
    freopen("block.in","r",stdin);
    freopen("block.out","w",stdout);
    scanf("%d",&n);
    for(int i=;i<=n;++i)
    {
        scanf("%d",&x1);
        if(x1>x2) ans+=x1-x2;
        x2=x1;
    } 
    printf("%I64d\n",ans);
    return ;
}

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define N 1000005

int n,a[N],ans;

int main()
{
    freopen("flower.in","r",stdin);
    freopen("flower.out","w",stdout);
    scanf("%d",&n);
    for(int i=;i<=n;++i) scanf("%d",&a[i]);
    short int flag=;ans=;
    for(int i=;i<=n-;++i)
    {
        if(a[i+]>=a[i]&&flag!=) 
            flag=,ans++;
        if(a[i+]<=a[i]&&flag!=)
            flag=,ans++;
    }
    printf("%d\n",ans);
    return ;
}

60分做法

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int n,m,p;
short int mp[][];
short int mark[][][][];
int xx[]={,,,-},yy[]={,-,,};
struct data
{
   int x,y,kx,ky;
   int step;
}q[810001];
bool jud(int x,int y,int kx,int ky)
{
    if(x<||y<||x>n||y>m||!mp[x][y]||!mp[kx][ky])return ;
    if(mark[x][y][kx][ky])return ;
    mark[x][y][kx][ky]=;
    return ;
}
void search()
{
    memset(mark,,sizeof(mark));
    int t=,w=;
    int ex,ey,x,y,kx,ky;
    scanf("%d%d%d%d%d%d",&q[0].kx,&q[0].ky,&q[0].x,&q[0].y,&ex,&ey);
    if(ex==q[0].x&&ey==q[0].y){printf("0\n");return;}
    mark[q[0].x][q[0].y][q[0].kx][q[0].ky]=;
    while(t<=w)
    {
        for(int i=;i<;++i)
        {
            x=q[t].x,y=q[t].y;
            kx=q[t].kx+xx[i],ky=q[t].ky+yy[i];
            if(x==kx&&y==ky){x=q[t].kx;y=q[t].ky;}
            if(jud(x,y,kx,ky))
            {
                w++;
                q[w].x=x;q[w].y=y;
                q[w].kx=kx;q[w].ky=ky;
                q[w].step=q[t].step+;
                if(x==ex&&y==ey){printf("%d\n",q[w].step);return;}
            }
        }
        t++;
    }
    printf("-1\n");
    return;
}
int main()
{
    freopen("puzzle.in","r",stdin);
    freopen("puzzle.out","w",stdout);
    scanf("%d%d%d",&n,&m,&p);
    for(int i=;i<=n;++i)
    for(int j=;j<=m;++j)
        scanf("%d",&mp[i][j]);
    for(int i=;i<=p;++i)
    {
        search();
    }
    return ;
}

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