new file: P2862.cpp

P2862.cpp

@@ -0,0 +1,74 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int c, n;
+pair<int, int> cc[505];
+int tmpx[505], tmpy[505];
+int sum[505][505];
+int totx, toty;
+bool check(int len)
+{
+    for (int i = 1; i <= totx; ++i)
+    {
+        int j = i;
+        while (j <= totx && tmpx[j] - tmpx[i] <= len - 1)
+            j++;
+        j--;
+        int l = 1;
+        for (int k = 1; k <= toty; ++k)
+        {
+            if (l < k)
+                l = k;
+            while (l <= toty && tmpy[l] - tmpy[k] <= len - 1)
+                l++;
+            l--;
+            if (l >= k)
+            {
+                int cnt = sum[j][l] - sum[i - 1][l] - sum[j][k - 1] + sum[i - 1][k - 1];
+                if (cnt >= c)
+                    return 1;
+            }
+        }
+    }
+    return 0;
+}
+
+int main()
+{
+    scanf("%d%d", &c, &n);
+    for (int i = 1; i <= n; ++i)
+    {
+        scanf("%d%d", &cc[i].first, &cc[i].second);
+        tmpx[i] = cc[i].first, tmpy[i] = cc[i].second;
+    }
+    sort(tmpx + 1, tmpx + n + 1);
+    totx = unique(tmpx + 1, tmpx + n + 1) - (tmpx + 1);
+    sort(tmpy + 1, tmpy + n + 1);
+    toty = unique(tmpy + 1, tmpy + n + 1) - (tmpy + 1);
+    memset(sum, 0, sizeof(sum));
+    for (int i = 1; i <= n; ++i)
+    {
+        int x = lower_bound(tmpx + 1, tmpx + totx + 1, cc[i].first) - tmpx;
+        int y = lower_bound(tmpy + 1, tmpy + toty + 1, cc[i].second) - tmpy;
+        sum[x][y]++;
+    }
+    for (int i = 1; i <= totx; ++i)
+    {
+        for (int j = 1; j <= toty; ++j)
+        {
+            sum[i][j] += sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1];
+        }
+    }
+    int L = 1, R = max(tmpx[totx] - tmpx[1] + 1, tmpy[toty] - tmpy[1] + 1), ans;
+    while (L <= R)
+    {
+        int mid = (L + R) / 2;
+        if (check(mid))
+            ans = mid, R = mid - 1;
+        else
+            L = mid + 1;
+    }
+
+    printf("%d\n", ans);
+    return 0;
+}