1 #include <cstdio> 2 #include <cstdlib> 3 #include <cmath> 4 #include <cstring> 5 #include <string> 6 #include <algorithm> 7 #include <iostream> 8 #include <iomanip> 9 #define For(i,j,k) for(int i=j;i<=k;i++) 10 #define Dow(i,j,k) for(int i=j;i>=k;i--) 11 #define LL long long 12 using namespace std ; 13 inline LL read() { 14 LL x = 0 , f = 1 ; 15 char ch = getchar() ; 16 while(ch<'0'||ch>'9') { if(ch=='-') f = -1 ; ch = getchar() ; } 17 while(ch>='0'&&ch<='9') { x = x * 10+ch-48 ; ch = getchar() ; } 18 return x * f ; 19 } 20 inline void write(LL x) { 21 if( x < 0 ) putchar('-') ; 22 if( x > 9 ) write(x/10) ; 23 putchar(x%10+48) ; 24 } 25 inline void writeln(LL x) { 26 write(x) ; 27 putchar(' ') ; 28 } 29 30 const int N = 100011; 31 int n,alpha; 32 struct node{ 33 int sum,id,rk; 34 }a[N]; 35 int tree[N*2]; 36 LL ans; 37 38 inline bool cmp_val(node a,node b) { 39 return a.sum < b.sum; 40 } 41 inline bool cmp_id(node a,node b) { 42 return a.id < b.id; 43 } 44 inline int lowbit(int x) { 45 return x&(-x); 46 } 47 inline void add(int x) { 48 for(; x<=n; x+=lowbit(x)) 49 ++tree[x]; 50 } 51 inline LL query(int x) { 52 LL res = 0; 53 for(; x; x-=lowbit(x)) 54 res+=tree[x]; 55 return res; 56 } 57 int main() { 58 n = read(); alpha = read(); 59 a[1].id = 1; a[1].sum = 0; 60 For(i, 2, n+1) { 61 int x = read(); a[i].sum = a[i-1].sum; 62 if( x >= alpha ) a[i].sum++; 63 else a[i].sum--; 64 a[i].id = i; 65 } 66 ++n; 67 sort(a+1, a+n+1, cmp_val); 68 a[0].sum = a[1].sum-1; 69 For(i, 1, n) { 70 a[i].rk = a[i-1].rk; 71 if(a[i].sum != a[i-1].sum) 72 ++a[i].rk; 73 } 74 sort(a+1, a+n+1, cmp_id); 75 For(i, 1, n) { 76 ans=ans+query(a[i].rk); 77 add(a[i].rk); 78 } 79 printf("%lld ",ans); 80 return 0; 81 } 82 83 84 /* 85 86 87 洛谷3031 88 高于中位数 89 树状数组 90 91 92 */