1 files changed, 146 insertions, 0 deletions
diff --git a/src/partition.rs b/src/partition.rs
new file mode 100644
index 0000000..10b4ab9
--- /dev/null
+++ b/src/partition.rs
@@ -0,0 +1,146 @@
+extern crate chrono;
+
+use std::collections::LinkedList;
+
+use chrono::NaiveDate;
+use chrono::Duration;
+
+#[cfg(test)]
+mod tests {
+
+    use std::collections::LinkedList;
+    use chrono::NaiveDate;
+
+    use super::partition;
+    use super::partition_days;
+
+    macro_rules! list {
+        ( $( $x:expr ),* ) => {
+            {
+                let mut temp_list = LinkedList::new();
+                $(
+                    temp_list.push_back($x);
+                )*
+                temp_list
+            }
+        };
+    }
+
+    #[test]
+    fn all_const1() {
+        let ins = vec![1, 2, 3, 4, 5, 6, 7, 8, 9];
+        let outs = list![list![1], list![2], list![3],
+                         list![4], list![5], list![6],
+                         list![7], list![8], list![9]];
+
+        assert_eq!(partition(&|_n| 1, &ins), outs);
+    }
+
+    #[test]
+    fn all_const2() {
+        let ins = vec![1, 2, 3, 4, 5, 6, 7, 8, 9];
+        let outs = list![list![1, 2], list![3, 4],
+                         list![5, 6], list![7, 8], list![9]];
+
+        assert_eq!(partition(&|_n| 2, &ins), outs);
+    }
+
+    #[test]
+    fn odds_const1() {
+        let ins = vec![1, 3, 5, 7, 9, 11, 13, 15];
+        let outs = list![list![1], list![], list![3], list![],
+                         list![5], list![], list![7], list![],
+                         list![9], list![], list![11], list![],
+                         list![13], list![], list![15]];
+
+        assert_eq!(partition(&|_n| 1, &ins), outs);
+    }
+
+    #[test]
+    fn odds_const2() {
+        let ins = vec![1, 3, 5, 7, 9, 11, 13, 15];
+        let outs = list![list![1], list![3], list![5],
+                         list![7], list![9], list![11],
+                         list![13], list![15]];
+
+        assert_eq!(partition(&|_n| 2, &ins), outs);
+    }
+
+    fn exp2(n: u32) -> i64 {
+        let i: i32 = n as i32 - 1;
+        2_f32.powi(i).ceil() as i64
+    }
+
+    #[test]
+    fn all_exp2() {
+        let ins = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13];
+        let outs = list![list![1], list![2, 3], list![4, 5, 6, 7],
+                         list![8, 9, 10, 11, 12, 13]];
+
+        assert_eq!(partition(&exp2, &ins), outs);
+    }
+
+    #[test]
+    fn dates_exp2() {
+        let d = NaiveDate::from_ymd;
+        let ins = vec![d(2019, 08, 30), d(2019, 08, 31),
+                       d(2019, 09, 01), d(2019, 09, 02),
+                       d(2019, 09, 03), d(2019, 09, 04)];
+        let outs = list![list![d(2019, 09, 04)],
+                         list![d(2019, 09, 03), d(2019, 09, 02)],
+                         list![d(2019, 09, 01), d(2019, 08, 31), d(2019, 08, 30)]];
+
+        assert_eq!(partition_days(&exp2, &ins), outs);
+    }
+}
+
+
+pub fn partition(f: &Fn(u32) -> i64, v: &Vec<i64>) -> LinkedList<LinkedList<i64>> {
+    let mut term: LinkedList<i64> = LinkedList::new();
+    let mut res: LinkedList<LinkedList<i64>> = LinkedList::new();
+    let mut n: u32 = 1;
+    let mut a: i64 = v[0];
+
+    for &i in v.iter() {
+        while i >= a + f(n) {
+            res.push_back(term);
+            term = LinkedList::new();
+            a += f(n);
+            n += 1;
+        }
+        term.push_back(i);
+    }
+    res.push_back(term);
+
+    res
+}
+
+pub fn partition_days(
+    f: &Fn(u32) -> i64,
+    days: &Vec<NaiveDate>,
+) -> LinkedList<LinkedList<NaiveDate>> {
+    let day1 = days[0];
+    let part;
+
+    {
+        let mut v: Vec<i64> = Vec::with_capacity(days.len());
+
+        for &d in days.iter() {
+            v.push((day1 - d).num_days());
+        }
+        v.sort_unstable();
+        v.dedup();
+
+        part = partition(f, &v);
+    }
+
+    let res = part.into_iter()
+        .map(|l| {
+            l.into_iter()
+                .map(|d| day1 - Duration::days(d))
+                .collect()
+        })
+        .collect();
+
+    res
+}