hdu 4417 Super Mario 二分+主席树第K小

题目链接

题意：n个数 m个询问  (n、m≤105n、m≤105)

每个询问有l, r, k  问的是[l, r]区间内有多少个数小于等于k

 

用主席树做的话查询第i小的数与k比较即可

 

///                 .-~~~~~~~~~-._       _.-~~~~~~~~~-.
///             __.'              ~.   .~              `.__
///           .'//                  \./                  \\`.
///        .'//                     |                     \\`.
///       .'// .-~"""""""~~~~-._     |     _,-~~~~"""""""~-. \\`.
///     .'//.-"                 `-.  |  .-'                 "-.\\`.
///   .'//______.============-..   \ | /   ..-============.______\\`.
/// .'______________________________\|/______________________________`.
#pragma GCC optimize("Ofast")
#pragma comment(linker, "/STACK:102400000,102400000")
#pragma GCC target(sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx) 
#include<bits/stdc++.h>
using namespace std;

#define pi acos(-1)
#define s_1(x) scanf("%d",&x)
#define s_2(x,y) scanf("%d%d",&x,&y)
#define s_3(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define s_4(x,y,z,X) scanf("%d%d%d%d",&x,&y,&z,&X)
#define S_1(x) scan_d(x)
#define S_2(x,y) scan_d(x),scan_d(y)
#define S_3(x,y,z) scan_d(x),scan_d(y),scan_d(z)
#define PI acos(-1)
#define endl '\n'
#define srand() srand(time(0));
#define me(x,y) memset(x,y,sizeof(x));
#define foreach(it,a) for(__typeof((a).begin()) it=(a).begin();it!=(a).end();it++)
#define close() ios::sync_with_stdio(0); cin.tie(0);
#define FOR(x,n,i) for(int i=x;i<=n;i++)
#define FOr(x,n,i) for(int i=x;i<n;i++)
#define fOR(n,x,i) for(int i=n;i>=x;i--)
#define fOr(n,x,i) for(int i=n;i>x;i--)
#define W while
#define sgn(x) ((x) < 0 ? -1 : (x) > 0)
#define bug printf("***********\n");
#define db double
//#define ll long long
#define mp make_pair
#define pb push_back
#define sz size
#define fi first
#define se second
#define pf printf
typedef long long LL;
typedef pair <int, int> ii;
const int INF=0x3f3f3f3f;
const LL LINF=0x3f3f3f3f3f3f3f3fLL;
const int dx[]={-1,0,1,0,1,-1,-1,1};
const int dy[]={0,1,0,-1,-1,1,-1,1};
const int maxn=1e2+7;
const int _=1e5+10;
const double EPS=1e-8;
const double eps=1e-8;
const LL mod=1e9+7;
template<class T>inline T min(T a,T b,T c) { return min(min(a,b),c);}
template<class T>inline T max(T a,T b,T c) { return max(max(a,b),c);}
template<class T>inline T min(T a,T b,T c,T d) { return min(min(a,b),min(c,d));}
template<class T>inline T max(T a,T b,T c,T d) { return max(max(a,b),max(c,d));}
template <class T>
inline bool scan_d(T &ret){char c;int sgn;if (c = getchar(), c == EOF){return 0;}
while (c != '-' && (c < '0' || c > '9')){c = getchar();}sgn = (c == '-') ? -1 : 1;ret = (c == '-') ? 0 : (c - '0');
while (c = getchar(), c >= '0' && c <= '9'){ret = ret * 10 + (c - '0');}ret *= sgn;return 1;}

inline bool scan_lf(double &num){char in;double Dec=0.1;bool IsN=false,IsD=false;in=getchar();if(in==EOF) return false;
while(in!='-'&&in!='.'&&(in<'0'||in>'9'))in=getchar();if(in=='-'){IsN=true;num=0;}else if(in=='.'){IsD=true;num=0;}
else num=in-'0';if(!IsD){while(in=getchar(),in>='0'&&in<='9'){num*=10;num+=in-'0';}}
if(in!='.'){if(IsN) num=-num;return true;}else{while(in=getchar(),in>='0'&&in<='9'){num+=Dec*(in-'0');Dec*=0.1;}}
if(IsN) num=-num;return true;}

void Out(LL a){if(a < 0) { putchar('-'); a = -a; }if(a >= 10) Out(a / 10);putchar(a % 10 + '0');}
void print(LL a){ Out(a),puts("");}
//cerr << "run time is " << clock() << endl;

int T[_],L[_<<5],R[_<<5],sum[_<<5];
int tot=0;
void build(int &rt,int l,int r) {
	rt=++tot;
	sum[rt]=0;
	if(l>=r) return ;
	int mid=(l+r)>>1;
	build(L[rt],l,mid);
	build(R[rt],mid+1,r);
}

void update(int &rt,int l,int r,int last,int pos,int val) {
	rt=++tot;
	L[rt]=L[last];
	R[rt]=R[last];
	sum[rt]=sum[last]+val;
	if(l>=r) return ;
	int mid=(l+r)>>1;
	if(pos<=mid) update(L[rt],l,mid,L[last],pos,val);
	else update(R[rt],mid+1,r,R[last],pos,val);
}

int query(int u,int v,int l,int r,int k) {
	if(l>=r) return l;
	int mid=(l+r)>>1;
	int tmp=sum[L[v]]-sum[L[u]];
	if(tmp>=k) 
		return query(L[u],L[v],l,mid,k);
	else 
		return query(R[u],R[v],mid+1,r,k-tmp);
}

int n,m;	
int a[_],Hash[_];
void solve() {
	s_2(n,m);
	tot=0;
	FOR(1,n,i) {
		s_1(a[i]);
		Hash[i]=a[i];
	}
	sort(Hash+1,Hash+1+n);
	int d=unique(Hash+1,Hash+n+1)-Hash-1;
	build(T[0],1,d);
	FOR(1,n,i) {
		int x=lower_bound(Hash+1,Hash+d+1,a[i])-Hash;
		update(T[i],1,d,T[i-1],x,1);
	}
	W(m--) {
		int l,r,k;
		s_3(l,r,k);
		l++,r++;
		int ll=1,rr=r-l+1,ans=0;
		W(ll<=rr) {
			int mm=(ll+rr)>>1;
			int tmp=Hash[query(T[l-1],T[r],1,d,mm)];
			if(tmp<=k) {
				if(mm==r-l+1||Hash[query(T[l-1],T[r],1,d,mm+1)]>k) {
					ans=mm;
					break;
				}
				ll=mm+1;
			}
			
			else {
				if(mm==1||Hash[query(T[l-1],T[r],1,d,mm-1)]<=k){
					ans=mm-1;
					break;
				}
				rr=mm-1;
			}
		}
		print(ans);
	}
}
int main() { 
	//freopen( "1.in" , "r" , stdin );
    //freopen( "1.out" , "w" , stdout );
    int t=1;
    //init();
    s_1(t);
    for(int cas=1;cas<=t;cas++) {
        printf("Case %d:\n",cas);
        solve();
    }
}