Data update

Task/Superpermutation-minimisation/Rust/superpermutation-minimisation.rs

@@ -0,0 +1,55 @@
+const MAX: usize = 12;
+
+// 1! + 2! + ... + n!
+fn fact_sum(n: usize) -> usize {
+    let mut sum = 0_usize;
+    let mut fact = 1_usize;
+    let mut x = 0_usize;
+    while x < n {
+        x += 1;
+        fact *= x;
+        sum += fact;
+    }
+    return sum;
+}
+
+fn r(n: usize, sup: &mut Vec<u8>, pos: &mut usize, cnt: &mut Vec<usize>) -> bool {
+    if n == 0 {
+        return false;
+    }
+    let c = sup[*pos - n];
+    cnt[n] -= 1;
+    if cnt[n] == 0 {
+        cnt[n] = n;
+        if !r(n - 1, sup, pos, cnt) {
+            return false;
+        }
+    }
+    sup[*pos] = c;
+    *pos += 1;
+    return true;
+}
+
+fn superperm(n: usize, sup: &mut Vec<u8>, pos: &mut usize, cnt: &mut Vec<usize>) -> usize {
+    *pos = n;
+    let new_len = fact_sum(n);
+    sup.resize(new_len, 0);
+    for i in 0..=n {
+        cnt[i] = i;
+    }
+    for i in 1..=n {
+        sup[i - 1] = (i as u8) + ('0' as u8);
+    }
+
+    while r(n, sup, pos, cnt) {}
+    return sup.len();
+}
+
+fn main() {
+    let sup: &mut Vec<u8> = &mut [0_u8; 0].to_vec();
+    let pos: &mut usize = &mut 0_usize;
+    let cnt: &mut Vec<usize> = &mut [0_usize; MAX].to_vec();
+    for n in 0..MAX {
+        println!("superperm of {:<2} has a length of {}", n, superperm(n, sup, pos, cnt));
+    }
+}