zju1360 Radar Installation

//zju1360 Radar Installation#include <cstdio>#include <algorithm>#include <functional>#include <cmath>using namespace std;#define MAX_N 1000#define PREC 1e-6char mark[MAX_N];struct NODE{double val;long id;inline bool operator< (const NODE& right) const { return val < right.val; }};NODE left[MAX_N];NODE right[MAX_N];int main(){long nCase = 0;long N, d;while (2 == scanf("%ld%ld", &N, &d)){if (0==N || 0==d) break;double dSqr = (double)(d*d);memset(mark, 0, N*sizeof(mark[0]));bool bNoSolut = false;long n;for (n=0; n<N; n++){long x, y;scanf("%ld%ld", &x, &y);if (bNoSolut) continue;if (y > d) { bNoSolut=true; continue; }double offset = sqrt(dSqr - (double)(y*y));left[n].val = x - offset;left[n].id = n;right[n].val = x + offset;right[n].id = n;}long nRadar = -1;if (!bNoSolut){sort(left, left+N, less<NODE>());sort(right, right+N, less<NODE>());nRadar = 0;long iLeft=0, iRight=0;while (1){double xRadar;for (;iRight<N; iRight++){if (!mark[ right[iRight].id ]){nRadar++;xRadar = right[iRight].val;mark[ right[iRight].id ] = 1;iRight++;break;}}if (iRight == N) break;for (;iLeft<N; iLeft++){double xLeft = left[iLeft].val;if (xLeft < xRadar || (xLeft-xRadar)<PREC)mark[ left[iLeft].id ] = 1;elsebreak;}if (iLeft == N) break;}}printf("Case %ld: %ld/n", ++nCase, nRadar);}return 0;}