Merge pull request #3211 from saa938/master

added python code

Author: SansPapyrus683

solutions/usaco-104.mdx

@@ -5,13 +5,15 @@ title: Haybale Stacking
 author: Óscar Garries, Brad Ma
 ---
 
-[Official Analysis](http://www.usaco.org/current/data/sol_stacking.html)
+[Official Analysis (Java)](http://www.usaco.org/current/data/sol_stacking.html)
+
+## Implementation
+
+**Time Complexity:** $\mathcal{O}(N\log N + K)$
 
 <LanguageSection>
 <CPPSection>
 
-## C++ Implementation
-
 ```cpp
 #include <bits/stdc++.h>
 
@@ -21,47 +23,46 @@ int main () {
 	int n, k;
 	cin >> n >> k;
 	vector<int> diff(n + 1);
-	for (int i = 0; i < k; i++) { // read input and build difference array
+	// read input and build difference array
+	for (int i = 0; i < k; i++) {
 		int l, r;
 		cin >> l >> r;
-		l--; // make zero-indexed
+		l--;  // make zero-indexed
 		r--;
 		diff[l]++;
 		diff[r + 1]--;
 	}
 
 	int sol[1000000];
 	int tot = 0;
-	for (int i = 0; i < n; i++) { // build prefix sum array
+	for (int i = 0; i < n; i++) {  // build prefix sum array
 		tot += diff[i];
 		sol[i] = tot;
 	}
-	sort (sol, sol + n); // sort to get median
-	cout << sol[n / 2] << '\n'; // output the median
+	sort (sol, sol + n);  // sort to get median
+	cout << sol[n / 2] << '\n';  // output the median
 }
 ```
 
 </CPPSection>
-	
 <JavaSection>
 
-## Java Implementation
-
 ```java
 import java.util.*;
 import java.io.*;
 
-class haybaleStacking {
+class HaybaleStacking {
 	public static void main (String[] args) {
 		Kattio io = new Kattio();
 
 		int n = io.nextInt();
 		int k = io.nextInt();
-		int[] differenceArray = new int[n + 1]; 
+		
 		// differenceArray[n] is the difference between A[n + 1] and A[n]
-
-		for (int x = 0; x < k; x++) { // read input and build differenceArray
-			int a = io.nextInt() - 1; // read and make zero-indexed
+		int[] differenceArray = new int[n + 1];
+		// read input and build differenceArray
+		for (int x = 0; x < k; x++) {
+			int a = io.nextInt() - 1;  // read and make zero-indexed
 			int b = io.nextInt() - 1;
 
 			differenceArray[a]++;
@@ -70,8 +71,7 @@ class haybaleStacking {
 
 		int[] prefixSum = new int[n + 1];
 		int total = 0;
-
-		for (int x = 0; x < n; x++) { // build prefixSum array
+		for (int x = 0; x < n; x++) {  // build prefixSum array
 			total += differenceArray[x];
 			prefixSum[x] = total;
 		}
@@ -81,11 +81,33 @@ class haybaleStacking {
 		io.close();
 	}
 
-	// CodeSnip{Kattio}
+	//CodeSnip{Kattio}
 }
 ```
 
 </JavaSection>
+<PySection>
+
+```py
+n, k = map(int, input().split())
+differences = [0] * (n + 1)  # make a difference array
+for i in range(k):
+	start, end = map(int, input().split())
+	# add one to the start
+	differences[start - 1] += 1
+	# subtract one from the next number outside of start - end
+	differences[end] -= 1
+
+pref = [0] * n  # prefix sums array
+s = 0	
+# uses differences and total sum to get where all the haybales are
+for i in range(n):
+	pref[i] = differences[i] + s 
+	s += differences[i]
+pref.sort() 
+
+print(pref[n // 2])
+```
 	
+</PySection>
 </LanguageSection>
-