P5101

Author: fei0319

code/luogu/P5101.rs

@@ -0,0 +1,137 @@
+use std::{
+    cmp::max,
+    io::{self},
+};
+
+pub struct Reader {
+    buffer: Vec<String>,
+}
+
+impl Reader {
+    pub fn new() -> Self {
+        Self { buffer: Vec::new() }
+    }
+    pub fn next<T: std::str::FromStr>(&mut self) -> T {
+        loop {
+            if let Some(token) = self.buffer.pop() {
+                return token.parse().ok().expect("Failed to parse token");
+            }
+            let mut input = String::new();
+            io::stdin()
+                .read_line(&mut input)
+                .expect("Failed to read line");
+            self.buffer = input.split_whitespace().rev().map(String::from).collect();
+        }
+    }
+}
+
+struct Counter {
+    cnt: Vec<usize>,
+    buf: Vec<Vec<usize>>,
+}
+impl Counter {
+    pub fn new(n: usize) -> Self {
+        let mut res = Self {
+            cnt: vec![0; n],
+            buf: vec![Vec::new()],
+        };
+        for i in 0..n {
+            res.buf[0].push(i);
+        }
+        res
+    }
+    pub fn add(&mut self, x: usize) {
+        self.cnt[x] += 1;
+        if self.buf.len() <= self.cnt[x] {
+            self.buf.push(Vec::new());
+        }
+        self.buf[self.cnt[x]].push(x);
+    }
+    pub fn del(&mut self, x: usize) {
+        self.cnt[x] -= 1;
+        self.buf[self.cnt[x]].push(x);
+    }
+    pub fn max_occurence(&mut self) -> usize {
+        loop {
+            let buf_len = self.buf.len();
+            let last_buf = self.buf.last_mut().unwrap();
+            while !last_buf.is_empty() && self.cnt[*last_buf.last().unwrap()] != buf_len - 1 {
+                last_buf.pop();
+            }
+            if last_buf.is_empty() {
+                self.buf.pop();
+            } else {
+                break;
+            }
+        }
+        self.buf.len() - 1
+    }
+}
+
+fn main() {
+    let mut reader = Reader::new();
+
+    let n = reader.next();
+    let m = reader.next();
+    let mut c = vec![0_usize; n];
+    for i in c.iter_mut() {
+        *i = reader.next::<usize>() - 1;
+    }
+
+    let mut counter = Counter::new(m);
+    for color in c.iter() {
+        counter.add(*color);
+    }
+
+    let mut ans = vec![0_usize; m];
+    for b in 0..2 {
+        let mut pairs_of_color = vec![vec![]; m];
+
+        let mut i = b + 1;
+        while i < n {
+            let pair = [c[i - 1], c[i]];
+            pairs_of_color[pair[0]].push(pair);
+            if pair[1] != pair[0] {
+                pairs_of_color[pair[1]].push(pair);
+            }
+            i += 2;
+        }
+
+        for color in 0..m {
+            let pairs = &pairs_of_color[color];
+            let mut res = 0;
+            if b == 1 && c[0] == color {
+                res += 1;
+                counter.del(color);
+            }
+            if n % 2 != b && c[n - 1] == color {
+                res += 1;
+                counter.del(color);
+            }
+            for pair in pairs {
+                pair.iter().for_each(|&x| {
+                    if x == color {
+                        res += 1;
+                    }
+                    counter.del(x);
+                });
+            }
+            ans[color] = max(ans[color], res + counter.max_occurence());
+            for pair in pairs {
+                pair.iter().for_each(|&x| {
+                    if x == color {
+                        res -= 1;
+                    }
+                    counter.add(x);
+                });
+            }
+            for _ in 0..res {
+                counter.add(color);
+            }
+        }
+    }
+
+    for color in 0..m {
+        println!("{}", n - ans[color]);
+    }
+}