hdu 4819 Mosaic

无论是线段树还是树状数组维护最大值最小值的时候一定要注意，如果有修改操作的话，这个最小值和最大值的更新一定不能由原来的和修改的值得到，一定要重新查询一次，否则可能出现当前最小值是原来的未修改值，但事实上若修改了，此最小值不存在了。此题线段树套线段树，写的代码有点挫了。

#include<cstdio>
#include<cstdlib>
#include<iostream>
#include<string>
#include<set>
#include<algorithm>
#include<vector>
#include<queue>
#include<list>
#include<cmath>
#include<cstring>
#include<map>
#include<stack>
using namespace std;
#define INF 0x3f3f3f3f
#define maxn 805
#define ull unsigned long long
#define ll long long
#define hashmod 99999839
#define mod 7
#define repe(x,y,i) for(i=x;i<=y;++i)
#define repne(x,y,i) for(i=x;i<y;++i)
#define MAX(x,y) (x) < (y) ? (y) : (x);
#define MIN(x,y) (x) < (y) ? (x) : (y);
int rson[maxn<<2][2],nex[maxn<<2],lenr,lenc,rootr;
int cson[(maxn*maxn)<<2][2],mi[(maxn*maxn)<<2],ma[(maxn*maxn)<<2];
int a[maxn][maxn],n,ls,rs,fa,x,y,z;
int cx,cy,rx,ry;
inline void pushup(int o){
    ls = cson[o][0],rs = cson[o][1];
    mi[o] = MIN(mi[ls],mi[rs]);
    ma[o] = MAX(ma[ls],ma[rs]);
}
void find(int o){
    int l = 1,r = n,mid = (l + r) >> 1;
    while(l < r){
        if(mid < x) o = cson[o][1],l = mid + 1;
        else o = cson[o][0],r = mid;
        mid = (l + r) >> 1;
    }
    x = mi[o],y = ma[o];
}
int buildc(int l,int r){
    int o = lenc;
    lenc++;
    if(l == r){//其最小,最大值可由行树的左右子树的根指向的列树中得到
        if(rx == ry) mi[o] = ma[o] = a[rx][l];//如果是同一行则直接得到
        else{
            mi[o] = INF,ma[o] = -1;
            ls = nex[rson[fa][0]],rs = nex[rson[fa][1]];
            x = l,y = r;
            find(ls);
            mi[o] = MIN(mi[o],x);
            ma[o] = MAX(ma[o],y);
            x = l,y = r;
            find(rs);
            mi[o] = MIN(mi[o],x);
            ma[o] = MAX(ma[o],y);
        }
        cson[o][0] = cson[o][1] = -1;
        return o;
    }
    int mid = (l + r) >> 1;
    cson[o][0] = buildc(l,mid),cson[o][1] = buildc(mid+1,r),pushup(o);
    return o;
}
int buildr(int l,int r){
    int o = lenr;
    lenr++;
    if(l == r){
        rson[o][0] = rson[o][1] = -1,fa = o,rx = l,ry = r;
        nex[o] = buildc(1,n);
        return o;
    }
    int mid = (l + r) >> 1;
    rson[o][0] = buildr(l,mid),rson[o][1] = buildr(mid+1,r),fa = o,rx = l,ry = r;
    nex[o] = buildc(1,n); 
    return o;
}
void queryc(int o,int l,int r){
    if(r < cx || l > cy) return;
    if(l >= cx && r <= cy){x = MIN(x,mi[o]);y = MAX(y,ma[o]);return;}
    int mid = (l + r) >> 1;
    queryc(cson[o][0],l,mid),queryc(cson[o][1],mid+1,r);
}
void queryr(int o,int l,int r){
    if(r < rx || l > ry) return;
    if(l >= rx && r <= ry){ queryc(nex[o],1,n);return;}
    int mid = (l + r) >> 1;
    queryr(rson[o][0],l,mid),queryr(rson[o][1],mid+1,r);
}
void updatec(int o,int l,int r){
    if(l == r){
        if(rx == ry) mi[o] = ma[o] = z;
        else {
            mi[o] = INF,ma[o] = -1;
            ls = nex[rson[fa][0]],rs = nex[rson[fa][1]];
            int tx = x,ty = y;
            x = l,y = r;
            find(ls);
            mi[o] = MIN(mi[o],x);
            ma[o] = MAX(ma[o],y);
            x = l,y = r;
            find(rs);
            mi[o] = MIN(mi[o],x);
            ma[o] = MAX(ma[o],y);
            x = tx,y = ty;
        }
        return;
    }
    int mid = (l + r) >> 1;
    if(mid >= y) updatec(cson[o][0],l,mid);
    else updatec(cson[o][1],mid+1,r);
    pushup(o);
}
void updater(int o,int l,int r){
    if(l == r){rx = ry = l,fa = o,updatec(nex[o],1,n);return;}
    int mid = (l + r) >> 1;
    if(mid >= x) updater(rson[o][0],l,mid);
    else updater(rson[o][1],mid+1,r);
    rx = l,ry = r,fa = o;
    updatec(nex[o],1,n);
}
int main(){
    freopen("a.in","r",stdin);
    freopen("b.out","w",stdout);
    int q,t = 0,T;
    scanf("%d",&T);
    register int i,j;
    while(T--){
        scanf("%d",&n);
        repe(1,n,i) repe(1,n,j) scanf("%d",&a[i][j]);
        lenr = lenc = 0;
        rootr = buildr(1,n);
        scanf("%d",&q);
        printf("Case #%d:
",++t);
        repe(1,q,i){
            scanf("%d%d%d",&x,&y,&z);
            rx = x - (z>>1),cx = y - (z>>1),ry = x + (z>>1),cy = y + (z>>1);
            if(rx <= 0) rx = 1;if(cx <= 0) cx = 1;if(ry > n) ry = n;if(cy > n) cy = n;
            int tx = x,ty = y;
            x = INF,y = -1,queryr(rootr,1,n),z = (x + y) >> 1,printf("%d
",z);
            x = tx,y = ty,updater(rootr,1,n);
        }
    }
    return 0;
}