CF: EduRound10: Nested Segments(data structure)

CF: EduRound10: Nested Segments(data structure) 

Idea: We have to find total segments withing main segment,

For this if we sort segments on the basis of which ends 

earlier comes first, we may easily get answer by updating

starting points withing segment range using BIT. 

 ///==================================================///
///                HELLO WORLD !!                    ///
///                  IT'S ME                         ///
///               BISHAL GAUTAM                      ///
///         [ bsal.gautam16@gmail.com ]              ///
///==================================================///
#include<bits/stdc++.h>
#define X first
#define Y second
#define mpp make_pair
#define nl printf("\n")
#define SZ(x) (int)(x.size())
#define pb(x) push_back(x)
#define pii pair<int,int>
#define pll pair<ll,ll>
///---------------------
#define S(a) scanf("%d",&a)
#define P(a) printf("%d",a)
#define SL(a) scanf("%lld",&a)
#define S2(a,b) scanf("%d%d",&a,&b)
#define SL2(a,b) scanf("%lld%lld",&a,&b)
///------------------------------------
#define all(v) v.begin(),v.end()
#define CLR(a) memset(a,0,sizeof(a))
#define SET(a) memset(a,-1,sizeof(a))
#define fr(i,a,n) for(int i=a;i<=n;i++)
using namespace std;
typedef long long ll;

///  Digit     0123456789012345678 ///
#define MX     200005
#define inf    2000000010
#define MD     1000000007
#define eps    1e-9
///===============================///

struct data {
    int x,y,id;
    data() {};
    data(int l,int r,int idx) {
        x=l,y=r,id=idx;
    }
    bool friend operator <(data A,data B) {
        if(A.y==B.y) return A.x>B.x;
        else return A.y<B.y;
    }
};
vector<int>v;
vector< data >vv;
int xx[MX+2],yy[MX+2],ans[MX+2],BIT[2*MX+5];

void add(int p,int v){
    for(int i=p;i<=MX+MX;i+=i&-i)BIT[i]+=v;
}

int read(int p){
    int ret=0;
    for(int i=p;i>0;i-=i&-i)ret+=BIT[i];
    return ret;
}

int main() {
    int n,x,y;
    S(n);
    for(int i=1; i<=n; i++) {
        S2(x,y);
        v.pb(x);
        v.pb(y);
        xx[i]=x,yy[i]=y;
    }
    sort( all(v) );
    v.resize( unique( all(v) )-v.begin() );
    for(int i=1; i<=n; i++) {
        x=lower_bound( all(v),xx[i] )-v.begin()+1;
        y=lower_bound( all(v),yy[i] )-v.begin()+1;
        vv.pb( data(x,y,i) );
    }
    sort( all(vv) );
    for(int i=0; i<n; i++) {
        ans[ vv[i].id ]=( read( vv[i].y )-read( vv[i].x ) );
        add( vv[i].x, +1 );
    }
    for(int i=1;i<=n;i++){
        printf("%d\n",ans[i]);
    }
    return 0;
}