increasing triplet subsequence

2022-aoc/src/d13.rs

@@ -66,15 +66,14 @@ fn parse_packet(scanner: &mut Scanner) -> Packet {
 
 fn parse_list(scanner: &mut Scanner) -> Vec<Element> {
     let mut out = Vec::new();
-    while !scanner.is_done() {
-        match scanner.peek().unwrap() {
+    while let Some(c) = scanner.peek() {
+        match c {
             '[' => {
                 scanner.pop();
                 let v = parse_list(scanner);
                 out.push(Element::List(v));
             }
             c if c.is_ascii_digit() => {
-                //
                 let mut s = String::new();
                 while let Some(c) = scanner.peek() {
                     if c.is_ascii_digit() {

increasing_triplet_subsequence/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "increasing_triplet_subsequence"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

increasing_triplet_subsequence/src/main.rs

@@ -0,0 +1,23 @@
+fn main() {
+    dbg!(increasing_triplet(&[1, 5, 2, 3]));
+}
+
+fn increasing_triplet(nums: &[i32]) -> bool {
+    let mut sub_seq = [i64::MAX; 4];
+    sub_seq[0] = i64::MIN;
+    for &v in nums {
+        let v = v as i64;
+        for j in 1..4 {
+            if sub_seq[j - 1] < v && v < sub_seq[j] {
+                sub_seq[j] = v;
+            }
+        }
+    }
+    let mut m = 0;
+    for &v in &sub_seq[1..] {
+        if v < i64::MAX {
+            m += 1;
+        }
+    }
+    m > 2
+}

product_of_array_except_self/src/main.rs

@@ -21,8 +21,8 @@ impl Solution {
             }
             Zeros::One(z) => {
                 let (left, right) = nums.split_at(z);
-                let left = if z == 0 { 1 } else { left.iter().product() };
-                let right = if z == nums.len() - 1 {
+                let left: i32 = left.iter().product();
+                let right: i32 = if right.len() < 2 {
                     1
                 } else {
                     right[1..].iter().product()
@@ -32,7 +32,7 @@ impl Solution {
                 }
                 nums[z] = left * right;
             }
-            _ => {}
+            Zeros::Many => *nums = vec![0; nums.len()],
         }
         out
     }
@@ -40,11 +40,12 @@ impl Solution {
 
 fn count_zeros(nums: &[i32]) -> Zeros {
     let mut out = Zeros::None;
-    let zs = 0;
+    let mut zs = false;
     for (i, n) in nums.iter().enumerate() {
         if *n == 0i32 {
-            if zs == 0 {
+            if !zs {
                 out = Zeros::One(i);
+                zs = true;
             } else {
                 out = Zeros::Many;
                 break;
@@ -57,4 +58,6 @@ fn count_zeros(nums: &[i32]) -> Zeros {
 fn main() {
     let p = Solution::product_except_self(vec![-1, 1, 0, -3, 3]);
     dbg!(p);
+    let p = Solution::product_except_self(vec![1, 2, 0, 3]);
+    dbg!(p);
 }