HDU 4325 Flowers(树状数组+离散化)

#include <iostream>
#include <cstdio>
#include <fstream>
#include <algorithm>
#include <cmath>
#include <deque>
#include <vector>
#include <queue>
#include <string>
#include <cstring>
#include <map>
#include <stack>
#include <set>
#include <list>
#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
8c45
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;
}