Completed solution.

src/main.rs

@@ -29,7 +29,7 @@ fn main() {
 	let mut boxes:Vec<u32> = Vec::with_capacity(size as usize);
 
 	{
-		let mut nums:Vec<u32> = (1..size+1).collect();
+		let mut nums:Vec<u32> = (0..size).collect();
 
 		while nums.len() > 0
 		{
@@ -38,4 +38,40 @@ fn main() {
 			nums.remove(rand_i);
 		}
 	}
+
+	let mut all_found = true;
+	for i in 0..size
+	{
+		let mut next_box:usize = i as usize;
+		let mut found = false;
+		for _j in 0..(size/2)
+		{
+			if boxes[next_box] == i
+			{
+				found = true;
+				break;
+			}
+			else
+			{
+				next_box = boxes[next_box] as usize;
+				if next_box == i as usize
+				{
+					break;
+				}
+			}
+		}
+		if !found
+		{
+			all_found = false;
+		}
+	}
+
+	if all_found
+	{
+		println!("All prisoners found their numbers!");
+	}
+	else
+	{
+		println!("Some prisoners didn't find their numbers!");
+	}
 }