HDU4417:Super Mario(主席树查询区间比k小的数的个数)

题意如标题所示，查询[i,j]区间内小于等于h的数的个数，是一道主席树的模板题，刚开始没离散化，直接用1e9建树T了，然后不太清醒的情况下写了2个小时离散化。。。

/*
 主席树查询小于等于k的数的个数; 
*/
#include
#include 
using namespace std;
#include
#include
#include
#include
int t,n,m,x,y,h,tot;
const int maxn = 1e5 + 10;
map<int,int> mp;
struct tt{
 	int ls,rs,val;
}tree[20 * maxn];
int root[maxn],cnt,a[maxn],b[maxn];
void init(){
 	mp.clear();
 	memset(root,0,sizeof(root));
 	root[0] = cnt = tot = 0;
 	tree[0].ls = tree[0].rs = tree[0].val = 0;
}
void update(int &rt,int k,int l,int r){
 	tree[++cnt] = tree[rt];
 	rt = cnt;
 	tree[rt].val++;
 	if(l == r) return;
 	int mid = l + r >> 1;
 	if(k > mid) update(tree[rt].rs,k,mid + 1,r);
 	else update(tree[rt].ls,k,l,mid);
}
int query(int i,int j,int k,int l,int r){
 	if(r <= k){
  		return tree[j].val - tree[i].val;
 	}
 	int res = 0;
 	int mid = l + r >> 1;
 	if(l <= k) res += query(tree[i].ls,tree[j].ls,k,l,mid);
 	if(mid + 1 <= k) res += query(tree[i].rs,tree[j].rs,k,mid + 1,r);
 	return res; 
}
int main(){
 	scanf("%d",&t);
 	int ce = 0;
 	while(t--){
 	 	printf("Case %d:\n",++ce);
  		scanf("%d%d",&n,&m);
  		init();
  		for(int i = 1; i <= n; i++){
   			scanf("%d",&a[i]);
   			b[i] = a[i];
  		}
  		sort(a + 1,a + n + 1);
  		for(int i = 1; i <= n; i++){
  	 		if(mp[a[i]]) continue;
   			mp[a[i]] = ++tot;
  		}
  		for(int i = 1; i <= n; i++){
   			root[i] = root[i - 1];
   			update(root[i],mp[b[i]],1,tot);
  		}
  		sort(b + 1,b + n + 1);
  		int p = unique(b + 1,b + n + 1) - b - 1;
  		b[0] = -10;
  		for(int i = 1; i <= m; i++){
   			scanf("%d%d%d",&x,&y,&h);
   			x++;y++;
   			int tmp = lower_bound(b + 1,b + p + 1,h) - b;
   			if(h != b[tmp]) tmp--;
   			h = b[tmp];
   			printf("%d\n",query(root[x - 1],root[y],mp[h],1,tot));
 	 	}
 	}
 	return 0;
}