y2015d12p2

y2015/src/days/d12.rs

@@ -13,76 +13,112 @@ pub fn process_part1(input: &str) -> i32 {
 }
 
 pub fn process_part2(input: &str) -> i32 {
-    let unreded_input = input
-        .split("red")
-        .map(|part| {
-            let open = find_open(part);
-            let close = find_close(part);
-            let new = &part[..open as usize];
-            &new[close as usize..]
-        })
-        .collect::<Vec<&str>>()
-        .join(", ");
-    println!("{unreded_input}");
+    let red_indices = input
+        .match_indices("red")
+        .map(|(idx, _)| idx)
+        .collect::<Vec<usize>>();
+    let mut red_objects = Vec::new();
+    let mut last_range = (0, 0);
+    for idx in red_indices {
+        if idx > last_range.0 && idx < last_range.1 {
+            continue;
+        }
+        let (left, right) = input.split_at(idx);
+        let open = find_open(left);
+        let close = find_close(right) + idx as u32;
+        let range = (open as usize, close as usize + 1);
+        last_range = range;
+        if !red_objects.contains(&range) {
+            red_objects.push(range);
+        }
+    }
+    red_objects.reverse();
+    // remove overlaps not caught during creation
+    let mut last_range = (0, 0);
+    let mut no_overlap = Vec::new();
+    for range in red_objects.clone() {
+        if last_range.0 < range.0 && last_range.1 > range.1 {
+            continue;
+        }
+        last_range = range;
+        no_overlap.push(range);
+    }
+    let mut unreded_input = input.to_owned();
+    for range in no_overlap {
+        unreded_input.replace_range(range.0..range.1, "0");
+    }
     process_part1(&unreded_input)
 }
 
 fn find_open(string: &str) -> u32 {
     let mut bytes = string.as_bytes().to_vec();
     bytes.reverse();
+    let length = bytes.len();
     // count of traversed objects
     // increments when seeing } decrements when seeing {
     // while == 0, potentially inside an object
     // while > 0 peeking inside another object
     // when < 0 left object red is inside of
     // when == 0 and encountered [ then inside array
-    let mut count = 0;
-    let mut idx = bytes.len() - 1;
-    for byte in bytes.clone() {
+    let mut curly_count = 0;
+    let mut square_count = 0;
+    let mut idx = length - 1;
+    for byte in bytes {
         if byte == b'}' {
-            count += 1
+            curly_count += 1
         } else if byte == b'{' {
-            count -= 1
-        } else if byte == b'[' && count == 0 {
-            return bytes.len() as u32 - 1;
+            curly_count -= 1
+        } else if byte == b'[' {
+            square_count -= 1;
+        } else if byte == b']' {
+            square_count += 1;
         }
-        if count < 0 || idx == 0 {
+        if square_count < 0 {
+            return length as u32 - 1;
+        }
+        if curly_count < 0 || idx == 0 {
             break;
         }
         idx -= 1;
     }
-    if count < 0 {
+    if curly_count < 0 {
         idx as u32
     } else {
-        bytes.len() as u32 - 1
+        length as u32
     }
 }
 
 fn find_close(string: &str) -> u32 {
     let bytes = string.as_bytes().to_vec();
+    let length = bytes.len();
     // count of traversed objects
     // increments when seeing { decrements when seeing }
     // while == 0, potentially inside an object
     // while > 0 peeking inside another object
     // when < 0 left object red is inside of
     // when == 0 and encountered ] then inside array
-    let mut count = 0;
+    let mut curly_count = 0;
+    let mut square_count = 0;
     let mut idx = 0;
-    for byte in bytes.clone() {
+    for byte in bytes {
         if byte == b'}' {
-            count -= 1
+            curly_count -= 1
         } else if byte == b'{' {
-            count += 1
-        } else if byte == b']' && count == 0 {
+            curly_count += 1
+        } else if byte == b']' {
+            square_count -= 1;
+        } else if byte == b'[' {
+            square_count += 1;
+        }
+        if square_count < 0 {
             return 0;
         }
-
-        if count < 0 || idx == bytes.len() - 1 {
+        if curly_count < 0 || idx == length {
             break;
         }
         idx += 1;
     }
-    if count < 0 {
+    if curly_count < 0 {
         idx as u32
     } else {
         0
@@ -115,22 +151,22 @@ mod tests_12 {
 
     #[test]
     fn part2() {
-        let result_a = process_part2("[1,2,3]");
-        let result_b = process_part2(r#"{"a":2,"b":4}"#);
-        assert_eq!(result_a, 6);
-        assert_eq!(result_b, 6);
-        let result_a = process_part2("[[[3]]]");
-        let result_b = process_part2(r#"{"a":{"b":4},"c":-1}"#);
-        assert_eq!(result_a, 3);
-        assert_eq!(result_b, 3);
-        let result_a = process_part2(r#"{"a":[-1,1]}"#);
-        let result_b = process_part2(r#"[-1,{"a":1}]"#);
-        assert_eq!(result_a, 0);
-        assert_eq!(result_b, 0);
-        let result_a = process_part2("[]");
-        let result_b = process_part2("{}");
-        assert_eq!(result_a, 0);
-        assert_eq!(result_b, 0);
+        //let result_a = process_part2("[1,2,3]");
+        //let result_b = process_part2(r#"{"a":2,"b":4}"#);
+        //assert_eq!(result_a, 6);
+        //assert_eq!(result_b, 6);
+        //let result_a = process_part2("[[[3]]]");
+        //let result_b = process_part2(r#"{"a":{"b":4},"c":-1}"#);
+        //assert_eq!(result_a, 3);
+        //assert_eq!(result_b, 3);
+        //let result_a = process_part2(r#"{"a":[-1,1]}"#);
+        //let result_b = process_part2(r#"[-1,{"a":1}]"#);
+        //assert_eq!(result_a, 0);
+        //assert_eq!(result_b, 0);
+        //let result_a = process_part2("[]");
+        //let result_b = process_part2("{}");
+        //assert_eq!(result_a, 0);
+        //assert_eq!(result_b, 0);
         let result_a = process_part2(r#"[1,{"c":"red","b":2},3]"#);
         assert_eq!(result_a, 4);
         let result_a = process_part2(r#"{"d":"red","e":[1,2,3,4],"f":5}"#);