Added Solution to codechef problem vanyaAndTheLanterns

MORE CODING PLATFORMS/Codeforces/vanyaAndTheLanterns/README.md

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+# [Vanya and the lanterns](https://codeforces.com/contest/492/problem/B)
+Vanya walks late at night along a straight street of length $l$, lit by $n$ lanterns. Consider the coordinate system with the beginning of the street corresponding to the point 0, and its end corresponding to the point $l$. Then the i-th lantern is at the point $a_i$. The lantern lights all points of the street that are at the distance of at most $d$ from it, where $d$ is some positive number, common for all lanterns.
+
+Vanya wonders: what is the minimum light radius d should the lanterns have to light the whole street?
+
+## Input
+The first line contains two integers $n, l$ ($1 ≤ n ≤ 1000, 1 ≤ l ≤ 109$) — the number of lanterns and the length of the street respectively.
+
+The next line contains n integers $a_i$ ($0 ≤ a_i ≤ l$). Multiple lanterns can be located at the same point. The lanterns may be located at the ends of the street.
+
+## Output
+Print the minimum light radius d, needed to light the whole street. The answer will be considered correct if its absolute or relative error doesn't exceed $10^{-9}$.
+
+## My solution
+- sort the array of $a_i$'s in ascending order and find the biggest distance between two consecutive lamposts. Divide this by two to get $d$. 
+- This algorithm only works when we have lamposts at $0$ and $l$, to cover all cases we have to define diff to be $max(A[0], l- A[n-1])$ where A is our array. 
+- This is because to biggest difference could be between the start of the street and the the first lampost or the last lampost and the end of the street.

MORE CODING PLATFORMS/Codeforces/vanyaAndTheLanterns/vanyaAndTheLanterns.cpp

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+#include <stdio.h>
+#include <algorithm>
+using namespace std;
+
+int n, l, i, indexes[1002], diff;
+
+int main ()
+{
+    scanf("%d%d", &n, &l);
+    for(i = 0; i < n; i++){
+        scanf("%d", &indexes[i]);
+    }
+    sort(indexes, indexes+n);
+    diff = 2*max(indexes[0], l - indexes[n-1]);
+    for(i = 0; i < n -1; i++){
+        diff = max(diff, indexes[i+1]- indexes[i]);
+    }
+    printf("%.10f\n", diff/2.);
+    return 0;
+}  

MORE CODING PLATFORMS/Codeforces/vanyaAndTheLanterns/vanyaAndTheLanterns.py

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+# 0 3 5 7 9 14 15
+
+
+
+from operator import index
+
+
+arr = input().split()
+n = int(arr[0])
+l = int(arr[1])
+indexes = [int(i) for i in input().split()]
+indexes.sort()
+diff = max(indexes[0], l-indexes[-1])
+for i in range(len(indexes)-1):
+    a = indexes[i+1] - indexes[i]
+    if a > diff:
+        diff = a
+print("{:.10f}".format(diff/2))