Create 398-random-pick-index.rs

Author: memorycancel

398-random-pick-index.rs

@@ -0,0 +1,37 @@
+use std::collections::HashMap;
+
+struct Solution {
+    mmp: HashMap<i32, Vec<usize>>
+}
+
+impl Solution {
+
+    fn new(nums: Vec<i32>) -> Self {
+        let mut mmp = HashMap::new();
+        for (i, num) in nums.iter().enumerate() {
+            mmp.entry(*num).or_insert(Vec::new()).push(i);
+        }
+        Solution {
+            mmp: mmp
+        }
+    }
+
+    fn pick(&mut self, target: i32) -> i32 {
+        self.mmp.get_mut(&target).unwrap().rotate_right(1);
+        self.mmp[&target][0] as i32
+    }
+}
+
+fn main() {
+    let mut obj = Solution::new(vec![1, 2, 3, 3, 3]);
+    println!("{:?}", obj.pick(3));
+    println!("{:?}", obj.pick(1));
+    println!("{:?}", obj.pick(3));
+    println!("{:?}", obj.pick(3));
+    println!("{:?}", obj.pick(3));
+    println!("{:?}", obj.pick(3));
+    println!("{:?}", obj.pick(3));
+    println!("{:?}", obj.pick(3));
+    println!("{:?}", obj.pick(3));
+    println!("{:?}", obj.pick(3));
+}