NOIP2017 Day2 小结

T1

并查集维护联通图

预计得分100

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#include<stdio.h>
#include<iostream>
#include<cmath>
#define FOR(i,s,t) for(register int i=s;i<=t;++i)
using namespace std;
typedef long long ll;
typedef double db;
const int BIG=2333;
int f[BIG];
int n,T;
int s1[BIG],s2[BIG];
struct node{
    ll x,y,z;
}p[BIG];
ll h,r;
int fi,fj;
inline int find(int x){
    return f[x]==x?x:f[x]=find(f[x]);
}
inline ll dis(int i,int j){
    return -1ll*r*r+1ll*(p[i].x-p[j].x)*(p[i].x-p[j].x)-1ll*r*r+1ll*(p[i].y-p[j].y)*(p[i].y-p[j].y)-1ll*r*r+1ll*(p[i].z-p[j].z)*(p[i].z-p[j].z)-1ll*r*r;
}
int main(){
    scanf("%d",&T);
    die:;
    while(T--){
        scanf("%d%lld%lld",&n,&h,&r);
        FOR(i,1,n)f[i]=i,s1[i]=s2[i]=0;
        FOR(i,1,n)scanf("%lld%lld%lld",&p[i].x,&p[i].y,&p[i].z);
        FOR(i,1,n)
            FOR(j,i+1,n){
                if(dis(i,j)<=0){
                    fi=find(i);
                    fj=find(j);
                    if(fi!=fj)f[fi]=fj;
                }
            }
        FOR(i,1,n){
            if(p[i].z-r<=0&&p[i].z+r>=0)
                s1[find(i)]=1;
            if(p[i].z-r<=h&&p[i].z+r>=h)
                s2[find(i)]=1;
        }
        FOR(i,1,n)
            if(s1[i]==1&&s2[i]==1){
                puts("Yes");
                goto die;
            }
        puts("No");
    }
    return 0;
}

T2

搜索+最优性剪枝

luogu上水过90

那就预计得分90

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#include<stdio.h>
#include<iostream>
#include<queue>
#include<algorithm>
#define FOR(i,s,t) for(register int i=s;i<=t;++i)
using namespace std;
int ans;
int dis[25][25];
int f[25];
int nxt[2333],las[25],to[2333],dep[25];
int w[2333];
int n,m,M;
int z;
int x,y,cnt,num,tot;
struct edge{
    int l;
    int r;
    int v;
    inline bool operator<(edge A)const{
        return v<A.v;
    }
}e[2333];
const int inf=(1<<28);
int p[2333];
inline void add(int x,int y,int z){
    nxt[++tot]=las[x];
    las[x]=tot;
    to[tot]=y;
    w[tot]=z;
}
inline int find(int x){
    return f[x]==x?x:find(f[x]);
}
queue<int>q;
inline void bfs(int s){
    int sum=0;
    while(!q.empty())q.pop();
    FOR(i,1,n)dep[i]=0;
    dep[s]=1;
    int now;
    q.push(s);
    while(!q.empty()){
        now=q.front();
        q.pop();
        for(register int e=las[now];e;e=nxt[e])
            if(!dep[to[e]]){
                dep[to[e]]=dep[now]+1;
                q.push(to[e]);
                sum=sum+1ll*w[e]*dep[now];
            }
    }
    ans=min(ans,sum);
}
inline void calc(){
    tot=0;
    for(register int i=1;i<=n;++i)
        las[i]=0;
    for(register int i=1;i<n;++i){
        add(e[p[i]].l,e[p[i]].r,e[p[i]].v);
        add(e[p[i]].r,e[p[i]].l,e[p[i]].v);
    }
    FOR(i,1,n)bfs(i);
}
inline void dfs(int t,int st,int sum){
    if(sum>=ans)
        return;
    if(t==n){  
        calc();
        return;
    }
    int l,r;
    for(register int i=st;i<=cnt;++i){
        l=find(e[i].l);
        r=find(e[i].r);
        if(l!=r){
            p[t]=i;
            f[l]=r;
            dfs(t+1,i+1,sum+e[i].v);
            f[l]=l;
        }
    }
}
inline int read(){
    char c;while(c=getchar(),c==' '||c=='\n');int data=c-48;
    while(c=getchar(),c>='0'&&c<='9')data=(data<<1)+(data<<3)+c-48;return data;
}
int main(){
    n=read();m=read();
    FOR(i,1,n)FOR(j,1,n)dis[i][j]=inf;
    FOR(i,1,n)dis[i][i]=0;
    FOR(i,1,n)f[i]=i;
    FOR(i,1,m){
        x=read();y=read();z=read();
        dis[x][y]=min(dis[x][y],z);
        dis[y][x]=min(dis[y][x],z);
    }
    FOR(i,1,n)FOR(j,i+1,n)if(dis[i][j]!=inf)e[++cnt]=(edge){i,j,dis[i][j]};
    sort(e+1,e+cnt+1);
    ans=inf;
    dfs(1,1,0);
    printf("%d\n",ans);
    return 0;
}

　　

T3

30分暴力+10分块状链表

好像块状链表写挂了

预计得分30

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#include<stdio.h>
#include<iostream>
#include<math.h>
#define FOR(i,s,t) for(register int i=s;i<=t;++i)
using namespace std;
int nxt[200005],af[200005],sz[2001],to[200005],be[2001];
const int big=1001;
int a[5001][5001];
int blo,cnt;
int n,m,t,num,x,y;
inline int read(){
    char c;while(c=getchar(),c==' '||c=='\n');int data=c-48;
    while(c=getchar(),c>='0'&&c<='9')data=(data<<1)+(data<<3)+c-48;return data;
}
inline void solve1(){
    blo=sqrt(m);
    FOR(i,1,m){
        if(i%blo==1)be[(i-1)/blo+1]=i;
        nxt[i]=i-1;
        ++sz[(i-1)/blo+1];
        to[i]=i;
        af[i]=i+1;
    }
    register int i,j;
    cnt=m;
    while(t--){
        x=read();y=read();
        for(i=1;i<=blo<<1|1;++i)
            if(y>sz[i])y-=sz[i];
            else break;
        for(j=be[i];;){
            --y;
            if(!y)break;
            j=af[j];
        }
        printf("%d\n",to[j]);
        ++cnt;
        if(cnt%blo==1)be[(cnt-1)/blo+1]=cnt;
        nxt[cnt]=cnt-1;
        ++sz[(cnt-1)/blo+1];
        to[cnt]=to[j];
        af[cnt]=cnt+1;
        nxt[af[j]]=nxt[j];
        af[nxt[j]]=af[j];
        --sz[(j-1)/blo+1];
        if(j%blo==1)
            be[(j-1)/blo+1]=af[j];
    }
    return;
}
inline void solve2(){
    FOR(i,1,n)FOR(j,1,m)a[i][j]=(i-1)*m+j;
        while(t--){
            x=read();y=read();
            num=a[x][y];
            a[x][y]=0;
            FOR(i,y,m)a[x][i]=a[x][i+1];
            FOR(i,x,n)a[i][m]=a[i+1][m];
            a[n][m]=num;
            printf("%d\n",num);
        }
}
int main(){
    n=read();m=read();t=read();
    if(n<=1000&&m<=1000){
        solve2();
        return 0;
    }
    if(n==1){
        solve1();
        return 0;
    }
    solve2();
    return 0;
}

　　

Day2得分100+90+30=220

NOIP2017总得分 100+50+30+100+90+30=400

Day2考得比Day1好[吐血]

posted @   Stump  阅读(316)  评论(0)  编辑  收藏  举报
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