UVALive

题意:给你一个矩阵,q次操作,每次查询长宽l的矩阵最大值a和最小值b,然后把中间点换成floor((a+b)/2),

解法:暴力可过,建n颗线段树暴力更新,但是正解应该是树套树,树套树需要注意的是当建树或修改时pushup操作不能直接搞,要先判断是不是外面层的叶子节点,如果是直接修改,如果不是,应该是从外面层的对应子节点更新过来,因为此时的外层树维护的是x轴区间最大和区间最小,需要从x轴两个更小的区间树合并起来更新

//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pi acos(-1.0)
#define ll long long
#define vi vector<int>
#define mod 1000000007
#define C 0.5772156649
#define ls l,m,rt<<1
#define rs m+1,r,rt<<1|1
#define pil pair<int,ll>
#define pli pair<ll,int>
#define pii pair<int,int>
#define cd complex<double>
#define ull unsigned long long
#define base 1000000000000000000
#define fio ios::sync_with_stdio(false);cin.tie(0)

using namespace std;

const double g=10.0,eps=1e-8;
const int N=800+10,maxn=5000+10,inf=0x3f3f3f3f,INF=0x3f3f3f3f3f3f3f3f;

int c[N][N],n;
struct segtreeinsegtree{
    int ma[N<<2][N<<2],mi[N<<2][N<<2];
    bool leaf;
    void pushupx(int id,int rt)
    {
        ma[id][rt]=max(ma[id<<1][rt],ma[id<<1|1][rt]);
        mi[id][rt]=min(mi[id<<1][rt],mi[id<<1|1][rt]);
    }
    void pushupy(int id,int rt)
    {
        ma[id][rt]=max(ma[id][rt<<1],ma[id][rt<<1|1]);
        mi[id][rt]=min(mi[id][rt<<1],mi[id][rt<<1|1]);
    }
    void buildy(int id,int x,int l,int r,int rt)
    {
        if(l==r)
        {
            if(leaf)ma[id][rt]=mi[id][rt]=c[x][l];
            else pushupx(id,rt);//,printf("%d %d %d %d
",id,x,ma[id][rt]);
            return ;
        }
        int m=(l+r)>>1;
        buildy(id,x,ls);buildy(id,x,rs);
        pushupy(id,rt);
    }
    void buildx(int xl,int xr,int rt,int yl,int yr)
    {
        if(xl==xr){leaf=1;buildy(rt,xl,yl,yr,1);return ;}
        int m=(xl+xr)>>1;
        buildx(xl,m,rt<<1,yl,yr);
        buildx(m+1,xr,rt<<1|1,yl,yr);
        leaf=0,buildy(rt,xl,yl,yr,1);
    }
    void updatey(int id,int posx,int posy,int c,int l,int r,int rt)
    {
        if(l==r)
        {
            if(leaf)ma[id][rt]=mi[id][rt]=c;
            else pushupx(id,rt);
            return ;
        }
        int m=(l+r)>>1;
        if(posy<=m)updatey(id,posx,posy,c,ls);
        else updatey(id,posx,posy,c,rs);
        pushupy(id,rt);
    }
    void updatex(int posx,int posy,int c,int l,int r,int rt)
    {
        if(l==r){leaf=1;updatey(rt,posx,posy,c,1,n,1);return ;}
        int m=(l+r)>>1;
        if(posx<=m)updatex(posx,posy,c,ls);
        else updatex(posx,posy,c,rs);
        leaf=0,updatey(rt,posx,posy,c,1,n,1);
    }
    int querymay(int id,int L,int R,int l,int r,int rt)
    {
        if(L<=l&&r<=R)return ma[id][rt];
        int m=(l+r)>>1,ans=0;
        if(L<=m)ans=max(ans,querymay(id,L,R,ls));
        if(m<R)ans=max(ans,querymay(id,L,R,rs));
        return ans;
    }
    int querymax(int xl,int xr,int yl,int yr,int l,int r,int rt)
    {
        if(xl<=l&&r<=xr){return querymay(rt,yl,yr,1,n,1);}
        int m=(l+r)>>1,ans=0;
        if(xl<=m)ans=max(ans,querymax(xl,xr,yl,yr,ls));
        if(m<xr)ans=max(ans,querymax(xl,xr,yl,yr,rs));
        return ans;
    }
    int querymiy(int id,int L,int R,int l,int r,int rt)
    {
        if(L<=l&&r<=R)return mi[id][rt];
        int m=(l+r)>>1,ans=1e9+10;
        if(L<=m)ans=min(ans,querymiy(id,L,R,ls));
        if(m<R)ans=min(ans,querymiy(id,L,R,rs));
        return ans;
    }
    int querymix(int xl,int xr,int yl,int yr,int l,int r,int rt)
    {
        if(xl<=l&&r<=xr)return querymiy(rt,yl,yr,1,n,1);
        int m=(l+r)>>1,ans=1e9+10;
        if(xl<=m)ans=min(ans,querymix(xl,xr,yl,yr,ls));
        if(m<xr)ans=min(ans,querymix(xl,xr,yl,yr,rs));
        return ans;
    }
    int query(int x,int y,int l)
    {
        int xl=max(1,x-l/2),xr=min(n,x+l/2);
        int yl=max(1,y-l/2),yr=min(n,y+l/2);
        int ma=querymax(xl,xr,yl,yr,1,n,1);
        int mi=querymix(xl,xr,yl,yr,1,n,1);
//        printf("%d %d
",ma,mi);
        int ans=floor(1.0*(ma+mi)/2);
        updatex(x,y,ans,1,n,1);
        return ans;
    }
    void debug(int id,int l,int r,int rt)
    {
        printf("%d %d %d %d
",l,r,ma[id][rt],mi[id][rt]);
        if(l==r)return ;
        int m=(l+r)>>1;
        debug(id,ls);debug(id,rs);
    }
}s;
int main()
{
    int T,cnt=0;scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&n);
        for(int i=1;i<=n;i++)
            for(int j=1;j<=n;j++)
                scanf("%d",&c[i][j]);
        s.buildx(1,n,1,1,n);
//        s.debug(5,1,n,1);
        int q;scanf("%d",&q);
        printf("Case #%d:
",++cnt);
        while(q--)
        {
            int x,y,l;
            scanf("%d%d%d",&x,&y,&l);
            printf("%d
",s.query(x,y,l));
        }
    }
    return 0;
}
/***********************
1
3
1 2 3
4 5 6
7 8 9
5
2 2 1
***********************/
View Code
原文地址:https://www.cnblogs.com/acjiumeng/p/8996936.html