poj1195 Mobile phones 二維樹狀數組

   做得有點苦逼，各種錯誤，但最後還是被我發現了

#include <iostream>#include<cstdio>#include<cstring>using namespace std;int c[1025][1025],n;inline int lowbit(int k){    return k&(-k);}void insert(int x,int y,int d){    for(int i=x;i<=n;i+=lowbit(i))        for(int j=y;j<=n;j+=lowbit(j))            c[i][j]+=d;}int getsum(int x,int y){    int t=0;    for(int i=x;i>0;i-=lowbit(i))        for(int j=y;j>0;j-=lowbit(j))            t+=c[i][j];    return t;}int main(){    int x1,y1,x2,y2,d,x;    while(~scanf("%d",&x))    {        if(x==3)            break;        if(x==0)        {            scanf("%d",&n);            //memset(c,0,sizeof(int)*(n+1)*(n+1));對於二維數組不能這樣初始化            for(int i=0;i<=n;i++)                for(int j=0;j<=n;j++)                    c[i][j]=0;        }        else if(x==1)        {            scanf("%d%d%d",&x1,&y1,&d);            x1++;y1++;            insert(x1,y1,d);        }        else        {            scanf("%d%d%d%d",&x1,&y1,&x2,&y2);            x1++;y1++;x2++;y2++;            int sum=getsum(x2,y2)-getsum(x1-1,y2)-getsum(x2,y1-1)+getsum(x1-1,y1-1);            printf("%d\n",sum);        }    }    return 0;}/*0 41 1 2 32 0 0 2 21 1 1 21 1 2 -12 1 1 2 33*/