837. 新 21 点

src/main.rs

@@ -1,69 +1,29 @@
-struct SegmentTree {
-    tree: Vec<i32>,
-    arr: Vec<i32>,
-}
-
-impl SegmentTree {
-    pub fn new(baskets: Vec<i32>) -> Self {
-        let n = baskets.len();
-        let size = 2 << (32 - (n as u32 - 1).leading_zeros());
-        let mut seg = SegmentTree {
-            tree: vec![0; size as usize],
-            arr: baskets.clone(),
-        };
-        seg.build(1, 0, n - 1);
-        seg
-    }
-
-    fn push_up(&mut self, o: usize) {
-        self.tree[o] = self.tree[o * 2].max(self.tree[o * 2 + 1]);
-    }
-
-    fn build(&mut self, o: usize, l: usize, r: usize) {
-        if l == r {
-            self.tree[o] = self.arr[l];
-            return;
-        }
-        let m = (l + r) / 2;
-        self.build(o * 2, l, m);
-        self.build(o * 2 + 1, m + 1, r);
-        self.push_up(o);
-    }
-
-    pub fn find_update(&mut self, o: usize, l: usize, r: usize, x: i32) -> Option<usize> {
-        if self.tree[o] < x {
-            return None;
-        }
-        if l == r {
-            self.tree[o] = -1;
-            return Some(l);
-        }
-        let m = (l + r) / 2;
-        let mut i = self.find_update(o * 2, l, m, x);
-        if i.is_none() {
-            i = self.find_update(o * 2 + 1, m + 1, r, x);
-        }
-        self.push_up(o);
-        i
-    }
-}
 struct Solution;
 impl Solution {
-    pub fn num_of_unplaced_fruits( fruits: Vec<i32>, baskets: Vec<i32>) -> i32 {
-        let n = baskets.len();
-        let mut tree = SegmentTree::new(baskets);
-        let mut ans = 0;
-
-        for fruit in fruits.iter() {
-            if tree.find_update(1,0,n-1,*fruit).is_none() {
-                ans += 1;
+    // return type: all situation, not crash situation
+    pub fn new21_game(n: i32, k: i32, max_pts: i32) -> f64 {
+        let mut mem = vec![0f64; (k + max_pts + 1) as usize];
+        for i in k .. k + max_pts + 1 {
+            mem[i as usize] = if i <= n { 1f64 } else { 0f64 };
         }
+        let mut temp_ans = 0f64;
+        if(k - 1 >= 0)
+        {
+            let i = k - 1;
+            for j in 1..max_pts + 1 {
+                temp_ans += mem[(i + j) as usize];
             }
-        ans
+            mem[i as usize] = temp_ans as f64 / max_pts as f64;
+        }
+        for i in (0..k - 1).rev() {
+            temp_ans += mem[(i + 1) as usize] - mem[(i + max_pts + 1) as usize];
+            mem[i as usize] = temp_ans as f64 / max_pts as f64;
+        }
+        mem[0]
     }
 }
 
 fn main() {
-    let sl = Solution::num_of_unplaced_fruits(vec![4,2,5],vec![3,5,4]);
+    let sl = Solution::new21_game(21, 17, 10);
     println!("{:?}", sl);
 }