120 lines
3.5 KiB
Rust
120 lines
3.5 KiB
Rust
struct DancingLinks<T: Copy + Eq> {
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cnt: usize,
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left: Vec<usize>,
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right: Vec<usize>,
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up: Vec<usize>,
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down: Vec<usize>,
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row_head: Vec<usize>,
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col_head: Vec<usize>,
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val: Vec<T>,
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row_info: Vec<usize>,
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col_info: Vec<usize>,
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}
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impl<T: Copy + Eq> DancingLinks<T> {
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fn new(max_n: usize) -> Self {
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let mut ins = Self {
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cnt: 0,
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left: vec![],
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right: vec![],
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up: vec![],
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down: vec![],
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row_head: vec![0;max_n],
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col_head: vec![0;max_n],
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val: vec![],
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row_info: vec![],
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col_info: vec![],
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};
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ins.left.push(0);
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ins.right.push(0);
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ins.up.push(0);
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ins.down.push(0);
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ins.row_info.push(0);
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ins.col_info.push(0);
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ins
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}
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fn get_item(&self, idx: usize) -> T {
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self.val[idx-1]
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}
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fn get(&self, i: usize, j: usize) -> Option<T> {
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let mut curr = self.row_head[i];
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while curr != 0 {
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if self.col_info[curr] == j {
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return Some(self.get_item(curr));
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}
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curr = self.right[curr];
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}
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curr = self.row_head[i];
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while curr != 0 {
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if self.col_info[curr] == j {
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return Some(self.get_item(curr));
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}
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curr = self.left[curr];
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}
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None
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}
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fn insert(&mut self, i: usize, j: usize, val: T) {
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self.cnt += 1;
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self.val.push(val);
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self.left.push(0);
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self.right.push(self.row_head[i]);
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self.left[self.row_head[i]] = self.cnt;
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self.row_head[i] = self.cnt;
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self.up.push(0);
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self.down.push(self.col_head[j]);
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self.up[self.col_head[j]] = self.cnt;
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self.col_head[j] = self.cnt;
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self.row_info.push(i);
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self.col_info.push(j);
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}
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fn remove_row(&mut self, i: usize) {
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let mut curr = self.row_head[i];
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while curr != 0 {
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self.down[self.up[curr]] = self.down[curr];
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self.up[self.down[curr]] = self.up[curr];
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curr = self.right[curr];
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}
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self.row_head[i] = 0;
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}
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fn remove_col(&mut self, j: usize) {
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let mut curr = self.col_head[j];
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while curr != 0 {
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self.right[self.left[curr]] = self.right[curr];
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self.left[self.right[curr]] = self.left[curr];
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curr = self.right[curr];
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}
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self.col_head[j] = 0;
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}
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fn dance_remove(&mut self, i: usize, plain: T) {
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let mut curr = self.row_head[i];
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while curr != 0 {
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if self.val[curr] != plain {
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let mut curr = self.col_head[self.col_info[curr]];
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while curr != 0 {
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if self.row_info[curr] != i && self.val[curr] != plain {
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self.remove_row(self.row_info[curr]);
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}
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curr = self.down[curr];
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}
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}
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self.remove_col(self.col_info[curr]);
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curr = self.right[curr];
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}
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self.remove_row(i);
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}
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}
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fn main() {
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let mut mat = DancingLinks::new(100);
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mat.insert(0,0,10086);
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mat.insert(0,1,234);
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mat.insert(1,1,10010);
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mat.insert(12,25,12345);
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assert_eq!(mat.get(0,0), Some(10086));
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assert_eq!(mat.get(1,0), None);
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assert_eq!(mat.get(12, 25), Some(12345));
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mat.dance_remove(0,0);
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assert_eq!(mat.get(0,0), None);
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assert_eq!(mat.get(1,0), None);
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assert_eq!(mat.get(1,1), None);
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} |