bzoj1935: [Shoi2007]Tree 园丁的烦恼

没什么好说的吧QWq

cdq分治

#include<cstdio> 
#include<algorithm> 
//using namespace std; 
inline int read()  {
    int x = 0,f = 1;
    char c = getchar() ;
    while(c < '0' || c > '9'){if(c == '-') f = -1; c = getchar();}  
    while(c <= '9' && c >= '0')x = x * 10 + c -'0',c = getchar(); 
    return x * f; 
} 
const int maxn = 500007; 
const int maxB = 10000003; 
struct Query { 
    int type,x,y,w,aid; 
    Query (int Type = 0,int X = 0,int Y = 0,int W = 0,int Aid = 0) : type(Type),x (X),y (Y),w (W),aid (Aid){}; 
    bool operator < (const Query & A) const { 
        return x == A.x ? type < A.type : x < A.x; 
    } 
} query[(maxn) * 5]; 
int maxy = -1;
namespace BIT { 
#define lowbit(x) (x & (-x)) 
    int sum[maxB << 1]; 
    void add(int idx,int val) { 
        for(;idx <= maxy;idx += lowbit(idx)) sum[idx] += val; 
    } 
    int query(int idx) { 
        int ret = 0; 
        for(;idx;idx -= lowbit(idx)) ret += sum[idx]; 
        return ret; 
    } 
    void clear(int idx) { 
        for( ;idx <= maxy;idx += lowbit(idx) ) 
            if(sum[idx]) sum[idx] = 0;else break; 
    }
} 
int ans[maxn];
Query tmp[maxn * 5 + 7];  
void cdq(int l,int r) { 
    if(r - l <= 1) return ;
    int mid = l + r >> 1; cdq(l,mid);cdq(mid,r); 
    int p = l,q = mid,cnt = l; 
    int sum  = 0 ;
    while(p < mid && q < r) { 
        if(query[p] < query[q]) { 
            if(query[p].type == 0) BIT::add(query[p].y,1); 
            tmp[cnt ++] = query[p ++]; 
        } else { 
            if(query[q].type == 1) ans[query[q].aid] += query[q].w * BIT::query(query[q].y); 
            tmp[cnt ++] = query[q ++]; 
        } 
    } 
    while(p < mid) tmp[cnt ++] = query[p ++]; 
    while(q < r)  { 
        if(query[q].type == 1) ans[query[q].aid] += query[q].w * BIT::query(query[q].y); 
        tmp[cnt ++] = query[q ++]; 
    } 
    for(int i = l;i < r;++ i) { 
        BIT:: clear(tmp[i].y); 
        query[i] = tmp[i]; 
    } 
} 
int n,m,qidx = 0,aidx; 
int main() { 
    n = read(),m = read(); 
    for(int x,y,i = 1;i <= n;++ i) { 
        x = read() + 1,y = read() + 1; 
        query[qidx ++] = Query(0,x,y,0,0);maxy = std::max(maxy,y); 
    } 
    for(int x1,y1,x2,y2,i = 1;i <= m;++ i) {
        x1 = read() + 1,y1 = read() + 1,x2 = read() + 1,y2 = read() + 1;
        query[qidx ++] = Query(1,x1 - 1,y1 - 1,1,aidx);
        query[qidx ++] = Query(1,x1 - 1,y2,- 1,aidx); 
        query[qidx ++] = Query(1,x2,y1 - 1,-1,aidx); 
        query[qidx ++] = Query(1,x2,y2,1,aidx); aidx ++; \
        maxy = std::max(maxy,std::max(y1,y2)); 
    } 
    cdq(0,qidx); 
    for(int i = 0;i < aidx;++ i) printf("%d\n",ans[i]); 
    return 0;
}