poj 2352 树状数组

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
using namespace std;

const int MAX_X = 32000 + 10;//注意这里
const int MAX_N = 15000;

struct Point{
int x, y;
};

int sum[MAX_X];
int ans[MAX_N+10];
Point p[MAX_N+10];
int N;

bool cmp( Point a, Point b ){
if( a.x < b.x ){
return true;
}else if( a.x > b.x ){
return false;
}else{
if( a.y < b.y ){
return true;
}else{
return false;
}
}
}

inline int lowbit( int x ){
return x&-x;
}

int getsum( int x ){
int ans = 0;
while( x > 0 ){
ans += sum[x];
x -= lowbit( x );
}
return ans;
}

void updata( int x, int val ){
while( x <= MAX_X ){
sum[x] += val;
x += lowbit( x );
}
}

int main(){
while( scanf( "%d", &N ) != EOF ){
for( int i = 1; i <= N; i++ ){
scanf( "%d%d", &p[i].x, &p[i].y );
p[i].x++;
p[i].y++;
}
memset( sum, 0, sizeof( sum ) );
sort( p + 1, p + 1 + N, cmp );
for( int i = 1; i <= N; i++ ){
ans[getsum(p[i].y)]++;
updata( p[i].y, 1 );
}
for( int i = 0; i < N; i++ ){
printf( "%d\n", ans[i] );
}
}
return 0;
}