Description
You are given n points and two circles. The radius of the circle will be dynamical. Your task is to find how many points are under both circles at each time.
A point is under a circle iff the point is strictly inside the circle or on the border of the circle.
Input Description
The first line of the input contains an integer T(1<=T<=20) which means the number of test cases.
For each case, the first line contains two integers n, m.(1 <= n, m <= 100000) Means the number of points and the number of queries.
Next n lines each contains two integer x, y(0 <= x, y <= 80000), describe a point.
Next line contains four integers x1, y1, x2, y2 (0 <= x1, y1, x2, y2 <= 80000), describe the center of two circles.
Next m lines each line contains two integers R1, R2, describe the radius of two circles.(1 <= R1, R2 <= 100000)
Output Description
For each query, output the number of points under both circles.
Sample Input
1 4 4 0 0 0 1 1 0 1 1 0 0 2 2 1 1 1 10 10 1 10 10
Sample Output
0 3 0 4碰见很多这样的题目了,哎,以为是几何题,题解出来了才发现是树状数组,多做做,多总结
1 #include<iostream> 2 #include<cstring> 3 #include<algorithm> 4 #include<cstdio> 5 #include<string> 6 #include<queue> 7 #include<cmath> 8 #include<vector> 9 10 using namespace std; 11 12 #define mnx 104000 13 #define ll long long 14 #define inf 0x3f3f3f3f 15 #define lson l, m, rt << 1 16 #define rson m+1, r, rt << 1 | 1 17 18 const int N = mnx; 19 struct point{ 20 int x, y; 21 point( int x = 0, int y = 0 ) : x(x), y(y) {} 22 point operator - ( const point &b ) const { 23 return point( x - b.x, y - b.y ); 24 } 25 int length(){ 26 ll len = (ll)x * x + (ll)y * y; 27 ll pt = sqrt( len ); 28 if( pt * pt < len ) pt++; 29 return (int)pt; 30 } 31 bool operator < ( const point & b ) const{ 32 return x < b.x; 33 } 34 }p[mnx], A, B; 35 struct rad{ 36 int r1, r2, id; 37 bool operator < ( const rad & b ) const{ 38 return r1 < b.r1; 39 } 40 }query[mnx]; 41 int bit[mnx]; 42 int sum( int x ){ 43 int ret = 0; 44 while( x > 0 ){ 45 ret += bit[x]; x -= x & -x; 46 } 47 return ret; 48 } 49 void add( int i, int x ){ 50 while( i <= N ){ 51 bit[i] += x; 52 i += i & -i; 53 } 54 } 55 int ans[mnx]; 56 int main(){ 57 int cas; 58 scanf( "%d", &cas ); 59 while( cas-- ){ 60 memset( bit, 0, sizeof(bit) ); 61 int n, m; 62 scanf( "%d %d", &n, &m ); 63 for( int i = 0; i < n; i++ ){ 64 scanf( "%d %d", &p[i].x, &p[i].y ); 65 } 66 scanf( "%d %d %d %d", &A.x, &A.y, &B.x, &B.y ); 67 for( int i = 0; i < n; i++ ){ 68 int dis1 = ( p[i] - A ).length(); 69 int dis2 = ( p[i] - B ).length(); 70 p[i] = point( dis1, dis2 ); 71 } 72 sort( p, p + n ); 73 for( int i = 0; i < m; i++ ){ 74 scanf( "%d %d", &query[i].r1, &query[i].r2 ); 75 query[i].id = i; 76 } 77 sort( query, query + m ); 78 int j = 0; 79 for( int i = 0; i < m; i++ ){ 80 while( j < n && p[j].x <= query[i].r1 ){ 81 add( p[j].y, 1 ); 82 j++; 83 } 84 ans[query[i].id] = sum( query[i].r2 ); 85 } 86 for( int i = 0; i < m; i++ ){ 87 printf( "%d\n", ans[i] ); 88 } 89 } 90 return 0; 91 }
Circle 树状数组