HDU 1556 Color the ball【树状数组】

题意：给出n个区间，每次给这个区间里面的数加1，询问单点的值

一维的区间更新，单点查询，还是那篇论文里面讲了的

#include<iostream>  
#include<cstdio>  
#include<cstring> 
#include <cmath> 
#include<stack>
#include<vector>
#include<map> 
#include<set>
#include<queue> 
#include<algorithm>  
using namespace std;

typedef long long LL;
const int INF = (1<<30)-1;
const int mod=1000000007;
const int maxn=100005;

int n;
int c[maxn];

int lowbit(int x){ return x &(-x);}

int sum(int x){
    int ret=0;
    while(x>0){
        ret+=c[x];x-=lowbit(x);
    }
    return ret;
}

void add(int x,int d){
    while(x<=n){
        c[x]+=d; x+=lowbit(x);
    }
}

int main(){
    while(scanf("%d",&n) != EOF){
        if(n == 0) break;
        memset(c,0,sizeof(c));
        for(int i=1;i<=n;i++){
            int a,b;
            scanf("%d %d",&a,&b);
            add(a,1);add(b+1,-1);
        }
        printf("%d",sum(1));
        for(int i=2;i <= n;i++)
        printf(" %d",sum(i));
        printf("
");
    }
    return 0;
}