new file: P1378.cpp

P1378.cpp

@@ -0,0 +1,54 @@
+#include <bits/stdc++.h>
+using namespace std;
+int n;
+pair<int, int> dro[10];
+bool used[10];
+double siz;
+double r[10];
+int x, y, xx, yy;
+double calc(int a, int b) {
+    return sqrt((dro[a].first - dro[b].first) * (dro[a].first - dro[b].first) +
+                (dro[a].second - dro[b].second) *
+                    (dro[a].second - dro[b].second)) -
+           r[b];
+}
+double ans = 4e6;
+void dfs(int now, int cnt) {
+    used[now] = 1;
+    double maxd = min(min(abs(dro[now].first - x), abs(dro[now].first - xx)),
+                      min(abs(dro[now].second - y), abs(dro[now].second - yy)));
+    for (int i = 1; i <= n; ++i) {
+        if (used[i] && i != now)
+            maxd = min(maxd, calc(now, i));
+    }
+    if (maxd < 0)
+        maxd = 0;
+    r[now] = maxd;
+    siz -= 3.1415926 * maxd * maxd;
+    if (cnt == n) {
+        ans = min(ans, siz);
+
+    } else {
+        for (int i = 1; i <= n; ++i) {
+            if (!used[i])
+                dfs(i, cnt + 1);
+        }
+    }
+    siz += 3.1415926 * maxd * maxd;
+    used[now] = 0;
+}
+int main() {
+    scanf("%d", &n);
+    scanf("%d%d%d%d", &x, &y, &xx, &yy);
+    x += 1000, y += 1000, xx += 1000, yy += 1000;
+    siz = abs((x - xx) * (y - yy));
+    for (int i = 1; i <= n; ++i) {
+        scanf("%d%d", &dro[i].first, &dro[i].second);
+        dro[i].first += 1000, dro[i].second += 1000;
+    }
+    for (int i = 1; i <= n; ++i) {
+        dfs(i, 1);
+    }
+    printf("%.0lf\n", ans);
+    return 0;
+}