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樹狀陣列---區間更新(差分陣列實現)

/*
* @Author: Achan
* @Date:   2018-10-28 12:55:01
* @Last Modified by:   Achan
* @Last Modified time: 2018-10-28 19:59:13
*/
#include<bits/stdc++.h>
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<iomanip>
#include<vector> 
#include
<queue>
#include<cmath> using namespace std; #define X first #define Y second #define eps 1e-2 #define gcd __gcd #define pb push_back #define PI acos(-1.0) #define lowbit(x) (x)&(-x) #define fin freopen("in.txt","r",stdin);
#define fout freopen("out.txt","w",stdout); #define bug printf("!!!!!\n"); #define mem(x,y) memset(x,y,sizeof(x)) #define rep(i,j,k) for(int i=j;i<(int)k;i++) #define per(i,j,k) for(int i=j;i<=(int)k;i++) #define pset(x) setiosflags(ios::fixed)<<setprecision(x) #define
io std::ios::sync_with_stdio(false),cin.tie(NULL),cout.tie(NULL);
typedef long long ll; typedef long double LD; typedef pair<int,int> pii; typedef unsigned long long ull; const int inf = 1<<30; const ll INF = 1e18 ; const int mod = 1e9+7; const int maxn = 1e5+2; const int mov[4][2] = {-1,0,1,0,0,1,0,-1}; const int Mov[8][2] = {-1,-1,-1,0,-1,1,0,-1,0,1,1,-1,1,0,1,1}; inline int read(){ int x=0,f=1;char ch=getchar(); while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();} while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();} return x*f; } int a[maxn]; bool vis[maxn]; int c[maxn]; //儲存排名資訊 int n; double rak[maxn]; int tree[maxn],tree1[maxn]; inline void update(int *c,int x, int val) { while(x<=n) { c[x] += val; x += (x& -x); } } inline int getsum(int *c,int x) { int sum = 0; while(x>0) { sum += c[x]; x -= x&(-x); } return sum; } int main(void) { //fin //fout io int T;cin>>T; while(T--) { cin>>n; memset(tree,0,sizeof(tree)); memset(tree1,0,sizeof(tree1)); for(int i=1; i<=n;i++) { cin>>a[i]; update(tree,a[i],1); //起始 update(tree,n+1,-1); //末尾 update(tree1,a[i],1*(a[i]-1)); //起始 update(tree1,n+1, -1*n); //末尾 int x,y; x=y=a[i]; rak[a[i]] = (y*getsum(tree,y)-(x-1)*getsum(tree,x-1))-(getsum(tree1,y)-getsum(tree1,x-1)) ; } // for(int i=1;i<=n; i++) cout<<rak[a[i]]<<endl; for(int i=1;i<=n;i++) { double rank = rak[a[i]]; double ex = (double)rank/(1.0 * i); double bex = 1.0 /(double)(n-i); // cout<<"rank "<<rank<<" "<<ex<<" "<<bex<<endl; if(ex < bex) { cout<<a[i]<<endl; break; } // else if(ex==bex) // { // cout<<min(a[i],a[i+1])<<endl; // break; // } } //printf("Case %d: ",cas++); //cout<<"Case #"<<cas++<<endl; } #ifdef LOCAL Debug("My Time: %.3lfms\n", (double)clock() / CLOCKS_PER_SEC); #endif }