樹狀數組【模板】

int lowbit(int t) { return t&(-t); } void change(int pos , int num,int n) //修改 { while (pos<=n) { tree[pos] += num; pos += lowbit(pos); } } int ask(int end)//查詢 { int sum = 0; while(end > 0) { sum += tree[end]; end -= lowbit(end); } return sum; }

 

下面是一個三維樹狀數組的例子：

 

 

 

#include <cstdio> #include <cstring> using namespace std; const int maxn=130; int s[maxn][maxn][maxn]; int N; inline int lowbit(int x){ return x&(x^(x-1)); } void change(int a,int b,int c,int delta){ for(int x=a;x<=N;x+=lowbit(x)) for(int y=b;y<=N;y+=lowbit(y)) for(int z=c;z<=N;z+=lowbit(z)) s[x][y][z]+=delta; } int sum(int a,int b,int c){ int res=0; for(int x=a;x>0;x-=lowbit(x)) for(int y=b;y>0;y-=lowbit(y)) for(int z=c;z>0;z-=lowbit(z)) res+=s[x][y][z]; return res; } int main(){ memset(s,0,sizeof(s)); scanf("%d",&N); for(;;){ int a; scanf("%d",&a); if(a==1){ int x,y,z,k; scanf("%d%d%d%d",&x,&y,&z,&k); ++x;++y;++z; change(x,y,z,k); } else if(a==2){ int x1,y1,z1,x2,y2,z2; scanf("%d%d%d%d%d%d",&x1,&y1,&z1,&x2,&y2,&z2); ++x2;++y2;++z2; printf("%d/n", sum(x2,y2,z2) -(sum(x1,y2,z2)+sum(x2,y1,z2)+sum(x2,y2,z1)) +(sum(x1,y1,z2)+sum(x1,y2,z1)+sum(x2,y1,z1)) -sum(x1,y1,z1) ); } else break; } }