complete 11049.rs

storage/zeta/rs/completed/11049.rs

@@ -0,0 +1,58 @@
+use std::io::stdin;
+
+fn split_by_2(s: &str) -> (usize, usize) {
+    let mut iter = s.split_ascii_whitespace();
+    (
+        iter.next().unwrap().parse().unwrap(),
+        iter.next().unwrap().parse().unwrap(),
+    )
+}
+
+fn get_mult_count(mat1: &(usize, usize), mat2: &(usize, usize)) -> usize {
+    // ensure that m1.c == m2.r
+    mat1.0 * mat1.1 * mat2.1
+}
+
+fn get_mat(mats: &Vec<(usize, usize)>, from: usize, to: usize) -> (usize, usize) {
+    (mats[from].0, mats[to].1)
+}
+
+fn get_minimum_mult_count(n: usize, mats: Vec<(usize, usize)>) -> usize {
+    let mut dp: Vec<Vec<usize>> = vec![vec![0; n]; n];
+
+    for interval in 1..n {
+        for i in 0..n - interval {
+            dp[i][i + interval] = *(0..interval)
+                .map(|split| {
+                    dp[i][i + split]
+                        + dp[i + split + 1][i + interval]
+                        + get_mult_count(
+                            &get_mat(&mats, i, i + split),
+                            &get_mat(&mats, i + split + 1, i + interval),
+                        )
+                })
+                .collect::<Vec<usize>>()
+                .iter()
+                .min()
+                .unwrap();
+        }
+    }
+
+    dp[0][n - 1]
+}
+
+fn main() {
+    let mut line = String::new();
+    stdin().read_line(&mut line).unwrap();
+    let n: usize = line.trim().parse().unwrap();
+
+    let mats: Vec<(usize, usize)> = (0..n)
+        .map(|_| {
+            let mut line = String::new();
+            stdin().read_line(&mut line).unwrap();
+            split_by_2(&line)
+        })
+        .collect();
+
+    println!("{}", get_minimum_mult_count(n, mats));
+}