//AC #include <stdio.h> #include <math.h> int main(int argc, const char * argv[]) { int m, n; int w, h; float from[10001], to[10001]; scanf("%d", &m); while (m--) { scanf("%d %d %d", &n, &w, &h); int k = 1; float x, r, t = h * 1.0 / 2, sq; for (int i = 0; i < n; i++) { scanf("%f %f", &x, &r); sq = sqrt(r * r - t * t); if (r > t) { from[k] = x - sq; to[k++] = x + sq; } } //排序 首要关键词 from 次要关键词 to for (int i = 1; i < k - 1; i++) { for (int j = i + 1; j < k; j++) { if (from[i] > from[j] || (from[i] == from[j] && to[i] < to[j])) { float temp = from[i]; from[i] = from[j]; from[j] = temp; temp = to[i]; to[i] = to[j]; to[j] = temp; } } } //判断区间头部是否覆盖 if (from[1] > 0) { printf("0\n"); continue; } int ans = 1; float flagT = to[1], flag = to[1]; from[k] = w; for (int i = 2; i < k; i++) { if (from[i] <= flagT && to[i] > flagT && to[i] > flag) //查找相对较大的区间 { flag = to[i]; } if (from[i + 1] > flagT) { flagT = flag; ans++; } } if (flagT < w) //判断区间尾部是否覆盖 { printf("0\n"); } else { printf("%d\n", ans); } } return 0; }