BOI 2007 mokia CDQ分治 or 二维树状数组 分析+代码

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<algorithm>
#include<iostream>
using namespace std;
int N,S[5000][5000];
int main()
{
      int sign;
      while(scanf("%d",&sign)!=EOF)
      {
            if(sign==0)
            {   
                  scanf("%d",&N);
                  memset(S,0,sizeof(S));
                  continue;
            }
            if(sign==1)
            {
                  int X,Y,V;
                  scanf("%d%d%d",&X,&Y,&V);
                  X++,Y++;
                  S[X][Y]+=V;
            }
            if(sign==2)
            {
                  int X1,Y1,X2,Y2,ans=0;
                  scanf("%d%d%d%d",&X1,&Y1,&X2,&Y2);
                  X1++,Y1++,X2++,Y2++;
                  for(int i=X1;i<=X2;i++)
                        for(int j=Y1;j<=Y2;j++)
                              ans+=S[i][j];
                  printf("%d\n",ans);    
            }
            if(sign==3)   break;
      }
      return 0;
}

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<algorithm>
#include<iostream>
using namespace std;
#define MAXN 5005
int N,S[MAXN][MAXN];
void add(int x,int y,int value)
{
      for(int i=x;i<=N+N/2;i+=(i&(-i)))
            for(int j=y;j<=N+N/2;j+=(j&(-j)))
                  S[i][j]+=value;
}
int getsum(int x,int y)
{
      int tmp=0;
      for(int i=x;i>=1;i-=(i&(-i)))
            for(int j=y;j>=1;j-=(j&(-j)))
                  tmp+=S[i][j];
      return tmp; 
}
int main()
{
      int sign;
      while(scanf("%d",&sign)!=EOF)
      {
            if(sign==0)
            {   
                  scanf("%d",&N);
                  continue;
            }
            if(sign==1)
            {
                  int X,Y,V;
                  scanf("%d%d%d",&X,&Y,&V);
                  X++,Y++;
                  add(X,Y,V);
            }
            if(sign==2)
            {
                  int X1,Y1,X2,Y2;
                  scanf("%d%d%d%d",&X1,&Y1,&X2,&Y2);
                  X1++,Y1++,X2++,Y2++;
                  printf("%d\n",getsum(X1-1,Y1-1)-getsum(X1-1,Y2)+getsum(X2,Y2)-getsum(X2,Y1-1));             
            }
            if(sign==3)   break;
      }
      return 0;
}

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<algorithm>
#include<iostream>
using namespace std;
#define MAX 640001
#define MAXN 2000001
#define MAXQ 60001
struct ASK{int num,x,y,v,kind,in;}a[MAX],T[MAX];
int sign,N,Q,tot=0,S[MAXN],ans[MAXQ];
void add(int x,int value){for(int i=x;i<=MAXN;i+=(i&(-i)))S[i]+=value;}
int getsum(int x){int tmp=0;for(int i=x;i>0;i-=(i&(-i)))tmp+=S[i];return tmp;};
bool cmp(ASK X,ASK Y){return X.x<Y.x;}
void addask(int num,int x,int y,int value,int kind)
{
      a[++tot].in=tot;
      a[tot].num=num;
      a[tot].x=x;
      a[tot].y=y;
      a[tot].v=value;
      a[tot].kind=kind;
}
void solve(int left,int right)
{
      if(left==right)   return;
      int middle=(left+right)/2,s1=left-1,s2=middle;
      for(int i=left;i<=right;i++)
      {
            if(a[i].in<=middle)
                 T[++s1]=a[i]; 
            else T[++s2]=a[i];
      }
      for(int i=left;i<=right;i++)
            a[i]=T[i];
      int now=left;
      for(int i=middle+1;i<=right;i++)
      {
            if(a[i].kind==2)
            {
                  while(a[now].x<=a[i].x && now<=middle)
                  {
                        if(a[now].kind==1)   add(a[now].y,a[now].v);
                        now++;
                  }
                  ans[a[i].num]+=a[i].v*getsum(a[i].y);
            }
      }
      now--;
      while(left<=now)
      {
            if(a[now].kind==1)
                  add(a[now].y,-a[now].v);
            now--;
      }
      solve(left,middle);
      solve(middle+1,right);
}
int main()
{
      while(scanf("%d",&sign)!=EOF)
      {
            if(sign==0)
            {   
                  if(tot)
                  {
                        sort(a+1,a+1+tot,cmp);
                        solve(1,tot);
                        for(int i=1;i<=Q;i++)
                              printf("%d\n",ans[i]);
                  }
                  scanf("%d",&N);
                  memset(ans,0,sizeof(ans));
                  memset(S,0,sizeof(S));
                  tot=0;Q=0;
                  continue;
            }
            if(sign==1)
            {
                  int X,Y,V;
                  scanf("%d%d%d",&X,&Y,&V);
                  X++,Y++;
                  addask(0,X,Y,V,1);
            }
            if(sign==2)
            {
                  int X1,Y1,X2,Y2;
                  scanf("%d%d%d%d",&X1,&Y1,&X2,&Y2);
                  X1++,Y1++,X2++,Y2++;Q++;
                  addask(Q,X1-1,Y1-1,1,2);  
                  addask(Q,X1-1,Y2,-1,2);
                  addask(Q,X2,Y2,1,2);
                  addask(Q,X2,Y1-1,-1,2);         
            }
            if(sign==3)   break;
      }
      sort(a+1,a+1+tot,cmp);
      solve(1,tot);
      for(int i=1;i<=Q;i++)
            printf("%d\n",ans[i]);
      return 0;
}

CDQ分治的详细分析可见：https://blog.youkuaiyun.com/csyzcyj/article/details/107298731

 

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