pastbook2 pastbook2022_c

cargo-compete/pastbook2/Cargo.toml

@@ -26,6 +26,7 @@ edition = "2018"
 128 = { alias = "tdpc_house", problem = "https://atcoder.jp/contests/tdpc/tasks/tdpc_house" }
 133 = { alias = "past202104_n", problem = "https://atcoder.jp/contests/past202104-open/tasks/past202104_n" }
 137 = { alias = "dp_x", problem = "https://atcoder.jp/contests/dp/tasks/dp_x" }
+143 = { alias = "pastbook2022_c", problem = "https://atcoder.jp/contests/pastbook2022/tasks/pastbook2022_c" }
 
 [[bin]]
 name = "027"
@@ -111,6 +112,10 @@ path = "src/bin/133.rs"
 name = "137"
 path = "src/bin/137.rs"
 
+[[bin]]
+name = "143"
+path = "src/bin/143.rs"
+
 [dependencies]
 num = "=0.2.1"
 num-bigint = "=0.2.6"

cargo-compete/pastbook2/README.md

@@ -22,3 +22,4 @@
 - P.128 家 (Typical DP Contest:M問題) <https://atcoder.jp/contests/tdpc/tasks/tdpc_house>
 - P.133 活動 (第六回 アルゴリズム実技検定:N問題) <https://atcoder.jp/contests/past202104-open/tasks/past202104_n>
 - P.137 Tower (Educational DP Contest:X問題) <https://atcoder.jp/contests/dp/tasks/dp_x>
+- P.143 各部分木の大きさ (オリジナル問題) <https://atcoder.jp/contests/pastbook2022/tasks/pastbook2022_c>

cargo-compete/pastbook2/src/bin/143.rs

@@ -0,0 +1,36 @@
+use proconio::{input, marker::Usize1};
+
+fn adjacency_list(n: usize, uv: &[(usize, usize)]) -> Vec<Vec<usize>> {
+    let mut edges = vec![vec![]; n];
+    for (u, v) in uv.iter().copied() {
+        edges[u].push(v);
+        edges[v].push(u);
+    }
+    edges
+}
+
+fn dfs(ans: &mut Vec<usize>, edges: &[Vec<usize>], u: usize, p: usize) {
+    ans[u] = 1_usize;
+    for v in edges[u].iter().copied() {
+        if v == p {
+            continue;
+        }
+        dfs(ans, edges, v, u);
+        ans[u] += ans[v];
+    }
+}
+
+fn main() {
+    input! {
+        n: usize,
+        ab: [(Usize1, Usize1); n - 1],
+    }
+
+    let edges = adjacency_list(n, &ab);
+    let mut ans = vec![0_usize; n];
+    dfs(&mut ans, &edges, 0, 0);
+
+    for a in ans {
+        println!("{}", a);
+    }
+}