3629. 通过质数传送到达终点的最少跳跃次数

src/main.rs

@@ -1,33 +1,105 @@
 mod arr;
-
 struct Solution {}
-impl Solution {
-    pub fn rotated_digits(n: i32) -> i32 {
-        let mut ans = 0;
-        let check = |mut x: i32| -> bool {
-            let mut is_diff = false;
-            while x != 0 {
-                let y = x % 10;
-                match y {
-                    2 => is_diff = true,
-                    3 => return false,
-                    4 => return false,
-                    5 => is_diff = true,
-                    6 => is_diff = true,
-                    7 => return false,
-                    9 => is_diff = true,
-                    _ => {}
-                }
-                x /= 10;
+
+use std::cmp::Ordering;
+use std::collections::{BinaryHeap, HashMap};
+
+#[derive(Eq, PartialEq)]
+struct Item(usize, usize); // (键, 值)
+impl Ord for Item {
+    fn cmp(&self, other: &Self) -> Ordering {
+        other.0.cmp(&self.0) // 反序，实现最小堆
+    }
+}
+
+impl PartialOrd for Item {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+static mut IS_PRIME: Vec<Vec<i32>> = vec![];
+
+pub fn get_is_prime() -> fn(i32) -> &'static Vec<i32> {
+    unsafe {
+        #![allow(static_mut_refs)]
+        if IS_PRIME.is_empty() {
+            let n = 1e6 as usize;
+            IS_PRIME = vec![vec![]; n + 1];
+            for i in 2..n + 1 {
+                IS_PRIME[i].push(1);
+                IS_PRIME[i].push(i as i32);
+            }
+            let mut primes = vec![0; n + 1];
+            let mut cnt = 0;
+
+            for i in 2..=n {
+                if IS_PRIME[i].len() == 2
+                //是素数采用来筛
+                {
+                    cnt += 1;
+                    primes[cnt] = i; //加入素数表
+                    for j in (2 * i..=n).step_by(i) {
+                        IS_PRIME[j].push(i as i32);
+                    }
+                }
             }
-            is_diff
-        };
-        for i in 1..=n {
-            ans += if check(i) { 1 } else { 0 }
         }
-        ans
+    }
+
+    // 返回函数指针，访问时再用 unsafe
+    fn check(x: i32) -> &'static Vec<i32> {
+        unsafe { &IS_PRIME[x as usize] }
+    }
+
+    check
+}
+
+impl Solution {
+    pub fn min_jumps(nums: Vec<i32>) -> i32 {
+        let mut arr = vec![1e6 as usize; nums.len()];
+        let mut map = HashMap::<i32, Vec<usize>>::new();
+        let is_prime = get_is_prime();
+        for i in 0..nums.len() {
+            if is_prime(nums[i]).len() == 2 {
+                map.entry(nums[i]).or_insert(vec![]).push(i);
+            }
+        }
+        // key 跳数 val 下标
+        let mut queue = BinaryHeap::new();
+        queue.push(Item(0, nums.len() - 1));
+
+        arr[nums.len() - 1] = 0;
+        while let Some(Item(jump_count, index)) = queue.pop() {
+            if index == 0 {
+                return jump_count as i32;
+            }
+            if index > 0 {
+                if arr[index - 1] > arr[index] + 1 {
+                    queue.push(Item(jump_count + 1, index - 1));
+                    arr[index - 1] = jump_count + 1;
+                }
+            }
+            if index < arr.len() - 1 {
+                if arr[index + 1] > arr[index] + 1 {
+                    queue.push(Item(jump_count + 1, index + 1));
+                    arr[index + 1] = jump_count + 1;
+                }
+            }
+
+            for i in is_prime(nums[index]).iter().skip(1) {
+                for x in map.entry(*i).or_default() {
+                    if arr[*x] > arr[index] + 1 {
+                        queue.push(Item(jump_count + 1, *x));
+                        arr[*x] = jump_count + 1;
+                    }
+                }
+                map.remove_entry(i);
+            }
+        }
+        0
     }
 }
 fn main() {
-    println!("{:?}", Solution::rotated_digits(10));
+    println!("{:?}", Solution::min_jumps(vec![5;1e5 as usize]));
 }