很典型的二维树状数组题,算是对优美的树状数组进行个总结吧
/*******************************************************************************
# Author : Neo Fung
# Email : neosfung@gmail.com
# Last modified: 2011-11-06 18:29
# Filename: POJ1195 Mobile phones.cpp
# Description :
******************************************************************************/
#include "stdafx.h"
#define DEBUG
#include <fstream>
#include <stdio.h>
#include <iostream>
#include <string.h>
#include <string>
#include <memory.h>
#include <limits.h>
#define lowbit(x) (x&(-x))
#define MAX 1030
using namespace std;
int n;
long long c[MAX][MAX];
long long getsum(const int &x,const int &y)
{
long long sum=0ll;
for(int i=x;i>0;i-=lowbit(i))
for(int j=y;j>0;j-=lowbit(j))
sum+=c[i][j];
return sum;
}
void updata(const int &x,const int &y,const int &val)
{
for(int i=x;i<=n;i+=lowbit(i))
for(int j=y;j<=n;j+=lowbit(j))
c[i][j]+=val;
}
int main(void)
{
#ifdef DEBUG
freopen("data.txt","r",stdin);
#endif
int instr;
int x,y,val,l,b,r,t;
while(scanf("%d",&instr) && instr!=3)
{
if(instr==0)
{
scanf("%d",&n);
memset(c,0,sizeof(c));
}
else if(instr==1)
{
scanf("%d%d%d",&x,&y,&val);
updata(x+1,y+1,val);
}
else
{
scanf("%d%d%d%d",&l,&b,&r,&t);
long long sum=getsum(r+1,t+1);
sum-=getsum(l,t+1);
sum-=getsum(r+1,b);
sum+=getsum(l,b);
printf("%lld\n",sum);
}
}
return 0;
}