noip2014总结

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终于有时间来总结一下noip2014了。。。。。。

蒟蒻360 SD 并列rank 76(无限仰慕fye神,TA神，Rivendell神。。。)

总结一下:

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Day1 T1,Day2 T2 水题两道，要做到又好又快。。。 code:

#include<cstdio>#include<cstring>#include<iostream>using namespace std;int a[201],b[201],n,na,nb;int main(){    int i,sca,scb;    freopen("rps.in","r",stdin);    freopen("rps.out","w",stdout);    memset(a,0,sizeof(a)); memset(b,0,sizeof(b));    scanf("%d%d%d",&n,&na,&nb);    for (i=1;i<=na;++i)      scanf("%d",&a[i]);    for (i=na+1;i<=n;++i)      a[i]=a[(i-1)%na+1];    for (i=1;i<=nb;++i)      scanf("%d",&b[i]);    for (i=nb+1;i<=n;++i)      b[i]=b[(i-1)%nb+1];    sca=0; scb=0;    for (i=1;i<=n;++i)      {        if (a[i]==0)          {            if ((b[i]==2)||(b[i]==3))              sca++;            if ((b[i]==1)||(b[i]==4))              scb++;          }        if (a[i]==1)          {            if ((b[i]==0)||(b[i]==3))              sca++;            if ((b[i]==2)||(b[i]==4))              scb++;          }        if (a[i]==2)          {            if ((b[i]==1)||(b[i]==4))              sca++;            if ((b[i]==0)||(b[i]==3))              scb++;          }        if (a[i]==3)          {            if ((b[i]==2)||(b[i]==4))              sca++;            if ((b[i]==0)||(b[i]==1))              scb++;          }        if (a[i]==4)          {            if ((b[i]==0)||(b[i]==1))              sca++;            if ((b[i]==2)||(b[i]==3))              scb++;          }      }    printf("%d %d\n",sca,scb);    fclose(stdin); fclose(stdout);    return 0;}

#include<iostream>#include<cstdio>#include<cstring>using namespace std;int map[200][200];int maxn,maxi,d,n;int main(){    int i,j,x,y,k,m,ans;    freopen("wireless.in","r",stdin);    freopen("wireless.out","w",stdout);    scanf("%d",&d);    memset(map,0,sizeof(map));    scanf("%d",&n);    for (i=1;i<=n;++i)      {        scanf("%d%d%d",&x,&y,&k);        map[x][y]=k;      }    maxn=0; maxi=0;    for (i=0;i<=128;++i)      for (j=0;j<=128;++j)        {          ans=0;          for (k=max(0,i-d);k<=min(128,i+d);++k)            for (m=max(0,j-d);m<=min(128,j+d);++m)              ans+=map[k][m];          if (ans==maxn)            maxi++;          if (ans>maxn)            {maxn=ans; maxi=1;}        }    printf("%d %d\n",maxi,maxn);    fclose(stdin); fclose(stdout);    return 0;}

link树形DP，但需要一些小技巧，DFS建树，穷举中间节点，处理同层和上下两层（考试想简单了，60）AC CODE:

#include<iostream>#include<cstdio>#include<cstring>using namespace std;int next[500000],point[250000];int a[250000]={0},n,ans,maxn;int e[500000];void treedp(int now,int last,int lastest,int sum){int j,c,maxf,maxs;ans=(ans+(a[now]*sum)%10007+(a[now]*a[lastest])%10007)%10007;maxn=max(maxn,a[now]*a[lastest]);j=point[now]; c=0; maxs=maxf=0;while (j!=0)  {    if (e[j]!=last)      {      treedp(e[j],now,last,c);        c=(c+a[e[j]])%10007;        if (a[e[j]]<=maxf&&a[e[j]]>maxs) maxs=a[e[j]];        if (a[e[j]]>maxf) {maxs=maxf; maxf=a[e[j]];}  }       j=next[j];      }maxn=max(maxn,maxf*maxs);}int main(){int i,x,y;freopen("linkb.in","r",stdin);freopen("linkb.out","w",stdout);memset(next,0,sizeof(next));memset(point,0,sizeof(point));scanf("%d",&n);for (i=1;i<=n-1;++i)  {    scanf("%d%d",&x,&y);     next[i*2-1]=point[x]; point[x]=i*2-1;next[i*2]=point[y]; point[y]=i*2;e[i*2-1]=y; e[i*2]=x;   }for (i=1;i<=n;++i)  scanf("%d",&a[i]);ans=0; maxn=0;treedp(1,0,0,0);ans=(ans*2)%10007;printf("%d %d",maxn,ans);fclose(stdin); fclose(stdout);}

road更简单，dfs判“连通”（考试竟然用floyed..... 60),跑一遍spfa即可 AC CODE:

#include<iostream>#include<cstdio>#include<cstring> using namespace std;struct hp{int u,v;}a[200001];int queue[100001],s,t,dis[100001]; int next1[200001],point1[100001],next2[200001],point2[100001],n,m;bool f[100001],ff[100001];void floodfill(int i){int j;f[i]=true; j=point1[i]; while (j!=0)  {  if (f[a[j].v]==false)      floodfill(a[j].v);    j=next1[j];  }}int spfa() {int head,tail,i,now,vi,y;memset(queue,0,sizeof(queue));memset(dis,127,sizeof(dis)); memset(f,false,sizeof(f)); head=0; tail=1; queue[tail]=s; y=dis[0];dis[s]=0; f[s]=true;while (head!=tail)  {    head=head%100000+1;    now=queue[head];    f[now]=false;    i=point2[now];    while (i!=0)      {        vi=a[i].u;        if (ff[vi]&&dis[vi]>dis[now]+1)          {            dis[vi]=dis[now]+1;            if (f[vi]==false)              {                f[vi]=true; tail=tail%100000+1;                queue[tail]=vi;              }          }        i=next2[i];      }      }if (dis[t]>=y) return -1;else return dis[t]; }int main(){int j,i,x,y;bool d;freopen("roadb.in","r",stdin); freopen("roadb.out","w",stdout);scanf("%d%d",&n,&m);memset(next1,0,sizeof(next1));memset(point1,0,sizeof(point2));memset(next2,0,sizeof(next1));memset(point2,0,sizeof(point2));memset(f,false,sizeof(f)); memset(ff,false,sizeof(ff)); for (i=1;i<=m;++i)  {    scanf("%d%d",&x,&y);    next1[i]=point1[y]; point1[y]=i;    next2[i]=point2[x]; point2[x]=i;    a[i].v=x; a[i].u=y;  }scanf("%d%d",&s,&t);  floodfill(t); for (i=1;i<=n;++i)  {    d=f[i];j=point2[i];while (j!=0)  {    d=d&&f[a[j].u];    j=next2[j];      }    ff[i]=d;  }printf("%d\n",spfa());fclose(stdin); fclose(stdout);}

Day1 T3完全背包,Day2 T3各种乱搞代码未写。。。。。。

1.加强对动归的练习 2.多了解一些数论知识 3.要建立起合适的数学模型，力求降低时间复杂度（前提是算对大O......)

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