HDU 4325 Flowers(树状数组+离散化)

#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include 
#include  
#include  
#include 
#define INF 0x3f3f3f
#define maxn 100000 + 50 
#define juzheng 300

#define ll long long

using namespace std;

//Date:2017-9-4
//Author：HarryBlackCat 

struct xx{
    int s;
    int e;
}time[maxn];

int arr[maxn],tree[maxn],que[maxn],n,m,counter;

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

void add(int index,int val,int n){
    for(int i = index;i <= n;i += lowbit(i))
        tree[i] += val;
}

int get_sum(int index){
    int ans = 0;
    for(int i = index ;i > 0; i -=lowbit(i))
        ans += tree[i];

    return ans; 
}

void init(){
    memset(arr,0,sizeof(arr));
    memset(tree,0,sizeof(tree));
    memset(que,0,sizeof(que));
    counter = 0; 
}

int main(){
    int t;
    while(cin >> t){
        for(int p = 1;p <= t;p++){
            init();

            cin >> n >> m;
            for(int i = 1;i <= n;i++){
                cin >> time[i].s >> time[i].e;
                //将时间段存入待处理的离散化数组 
                arr[++counter] = time[i].s; 
                arr[++counter] = time[i].e;
            }

            for(int i = 1;i <= m;i++){
                cin >> que[i];
                //将询问时间点存入待处理的离散化数组 
                arr[++counter] = que[i];
            } 

            //离散化处理 
            sort(arr + 1,arr + 1 + counter);//排序 
            int len = unique(arr + 1,arr + 1 + counter) - arr - 1;//去重,并记录去重后的长度 

            for(int i = 1;i <= n;i++){
                int s = lower_bound(arr + 1,arr + 1 + len,time[i].s) - arr - 1 + 1;//找到开始点在离散化数组的下标(+1是表示从1开始算起) 
                int e = lower_bound(arr + 1,arr + 1 + len,time[i].e) - arr - 1 + 1;//找到结束点在离散化数组的下标
                //利用树状数组储存离散化的区间 
                add(s,1,len);
                add(e + 1,-1,len);
            }

            printf("Case #%d:\n",p);
            for(int i = 1;i <= m;i++){
                int index = lower_bound(arr + 1,arr + 1 + len,que[i]) - arr - 1 + 1;//找到询问点的离散化数组中的下标 
                printf("%d\n",get_sum(index));//输出ans 
            }
        }
    }
    return 0;
}