add: 07, had to work today but srsly whats the fuzz with today

2025/07/p1.rs

@@ -0,0 +1,31 @@
+#[unsafe(no_mangle)]
+pub extern "Rust" fn challenge_usize(buf: &[u8]) -> usize {
+    let mut splits = 0;
+
+    let mut ln_iter = buf[0..(buf.len() - 1)].split(|&b| b == b'\n');
+
+    let first_line = ln_iter.next().unwrap();
+    let mut ray_boollist = Box::new_uninit_slice(first_line.len());
+    first_line
+        .iter()
+        .map(|&c| c == b'S')
+        .enumerate()
+        .for_each(|(i, b)| {
+            ray_boollist[i].write(b);
+        });
+    let mut ray_boollist = unsafe { ray_boollist.assume_init() };
+
+    for ln in ln_iter {
+        // dbg!(unsafe { str::from_utf8_unchecked(ln) }, splits);
+        for (i, _) in ln.iter().enumerate().filter(|&(_, &c)| c == b'^') {
+            if ray_boollist[i] {
+                splits += 1;
+                ray_boollist[i] = false;
+                ray_boollist.get_mut(i - 1).map(|b| *b = true);
+                ray_boollist.get_mut(i + 1).map(|b| *b = true);
+            }
+        }
+    }
+
+    splits
+}