From 47442f267eb3d98b74babc1e2b9422225b21d5f9 Mon Sep 17 00:00:00 2001
From: Kirito <1362050620@qq.com>
Date: Sun, 8 May 2016 20:48:13 +0800
Subject: [PATCH] Create 4932_lyhvoyage.cpp

From http://blog.csdn.net/lyhvoyage/article/details/38486961
---
 HDOJ/4932_lyhvoyage.cpp | 57 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 HDOJ/4932_lyhvoyage.cpp

diff --git a/HDOJ/4932_lyhvoyage.cpp b/HDOJ/4932_lyhvoyage.cpp
new file mode 100644
index 0000000..191b50d
--- /dev/null
+++ b/HDOJ/4932_lyhvoyage.cpp
@@ -0,0 +1,57 @@
+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+using namespace std;
+int main()
+{
+    double b[120], c[60];
+    int flag[60];
+    int n, i, j, T;
+    scanf("%d",&T);
+    while(T--)
+    {
+        scanf("%d",&n);
+        for(i = 0; i < n; i++)
+            scanf("%lf",&c[i]);
+        sort(c, c+n);
+        int m = 0;
+        for(i = 1; i < n; i++)
+        {
+            b[m++] = c[i] - c[i-1];
+            b[m++] = (c[i] - c[i-1]) / 2;
+        }
+        sort(b, b+m);
+        double ans;
+        for(i = m - 1; i >= 0; i--)
+        {
+            memset(flag, 0, sizeof(flag));
+            flag[0] = 1;
+            double tmp = b[i];
+            for(j = 1; j < n - 1; j++)
+            {
+                if(c[j] - tmp < c[j-1] && c[j] + tmp > c[j+1])  //往左往右都不行
+                    break;
+                if(c[j] - tmp >= c[j-1])
+                {
+                    if(flag[j-1] == 2) // 前一个往右
+                    {
+                        if(c[j] - c[j-1] == tmp) flag[j] = 1;  //两个点作为线段的两个端点
+                        else if(c[j] - c[j-1] >= 2 * tmp) flag[j] = 1; //一个往左，一个往右
+                        else if(c[j] + tmp <= c[j+1]) flag[j] = 2; //只能往右
+                        else break;
+                    }
+                    else flag[j] = 1;
+                }
+                else if(c[j] + tmp <= c[j+1])
+                    flag[j] = 2;
+            }
+            if(j == n - 1)
+            {
+                ans = tmp;
+                break;
+            }
+        }
+        printf("%.3lf\n", double(ans));
+    }
+    return 0;
+}