move

0x00/28.cpp

@@ -0,0 +1,34 @@
+// 112
+#include <bits/stdc++.h>
+using namespace std;
+int n, d;
+struct node
+{
+    int x, y;
+    double xl, xr;
+} is[1005];
+int main()
+{
+    scanf("%d%d", &n, &d);
+    for (int i = 1; i <= n; ++i)
+    {
+        scanf("%d%d", &is[i].x, &is[i].y);
+        if (abs(is[i].y) > d)
+        {
+            puts("-1");
+            return 0;
+        }
+        double len = sqrt(1.0 * d * d - 1.0 * is[i].y * is[i].y);
+        is[i].xl = is[i].x - len, is[i].xr = is[i].x + len;
+    }
+    sort(is + 1, is + n + 1, [](const node &x, const node &y)
+         { return x.xr < y.xr; });
+    int ans = 0;
+    double now = -DBL_MAX;
+    const double eps = 1e-10;
+    for (int i = 1; i <= n; ++i)
+        if (now + eps < is[i].xl)
+            now = is[i].xr, ++ans;
+    printf("%d\n", ans);
+    return 0;
+}