feat: add rust solution lc problems: No.1870,1894

* No.1870.Minimum Speed to Arrive on Time
* No.1894.Find the Student that Will Replace the Chalk

Author: maolonglong

solution/1800-1899/1870.Minimum Speed to Arrive on Time/README.md

@@ -270,6 +270,44 @@ func minSpeedOnTime(dist []int, hour float64) int {
 }
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn min_speed_on_time(dist: Vec<i32>, hour: f64) -> i32 {
+        let n = dist.len();
+
+        let check = |speed| {
+            let mut cur = 0.;
+            for (i, &d) in dist.iter().enumerate() {
+                if i == n - 1 {
+                    cur += d as f64 / speed as f64;
+                } else {
+                    cur += (d as f64 / speed as f64).ceil();
+                }
+            }
+            cur <= hour
+        };
+
+        let mut left = 1;
+        let mut right = 1e7 as i32;
+        while left < right {
+            let mid = left + (right - left) / 2;
+            if !check(mid) {
+                left = mid + 1;
+            } else {
+                right = mid;
+            }
+        }
+
+        if check(left) {
+            return left;
+        }
+        -1
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1800-1899/1870.Minimum Speed to Arrive on Time/README_EN.md

@@ -247,6 +247,44 @@ func minSpeedOnTime(dist []int, hour float64) int {
 }
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn min_speed_on_time(dist: Vec<i32>, hour: f64) -> i32 {
+        let n = dist.len();
+
+        let check = |speed| {
+            let mut cur = 0.;
+            for (i, &d) in dist.iter().enumerate() {
+                if i == n - 1 {
+                    cur += d as f64 / speed as f64;
+                } else {
+                    cur += (d as f64 / speed as f64).ceil();
+                }
+            }
+            cur <= hour
+        };
+
+        let mut left = 1;
+        let mut right = 1e7 as i32;
+        while left < right {
+            let mid = left + (right - left) / 2;
+            if !check(mid) {
+                left = mid + 1;
+            } else {
+                right = mid;
+            }
+        }
+
+        if check(left) {
+            return left;
+        }
+        -1
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1800-1899/1870.Minimum Speed to Arrive on Time/Solution.rs

@@ -0,0 +1,33 @@
+impl Solution {
+    pub fn min_speed_on_time(dist: Vec<i32>, hour: f64) -> i32 {
+        let n = dist.len();
+
+        let check = |speed| {
+            let mut cur = 0.;
+            for (i, &d) in dist.iter().enumerate() {
+                if i == n - 1 {
+                    cur += d as f64 / speed as f64;
+                } else {
+                    cur += (d as f64 / speed as f64).ceil();
+                }
+            }
+            cur <= hour
+        };
+
+        let mut left = 1;
+        let mut right = 1e7 as i32;
+        while left < right {
+            let mid = left + (right - left) / 2;
+            if !check(mid) {
+                left = mid + 1;
+            } else {
+                right = mid;
+            }
+        }
+
+        if check(left) {
+            return left;
+        }
+        -1
+    }
+}

solution/1800-1899/1894.Find the Student that Will Replace the Chalk/README.md

@@ -189,6 +189,27 @@ func chalkReplacer(chalk []int, k int) int {
 }
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn chalk_replacer(chalk: Vec<i32>, k: i32) -> i32 {
+        let pre_sum: Vec<i64> = chalk
+            .into_iter()
+            .map(|x| x as i64)
+            .scan(0, |state, x| {
+                *state += x;
+                Some(*state)
+            })
+            .collect();
+
+        pre_sum
+            .binary_search(&(k as i64 % pre_sum.last().unwrap()))
+            .map_or_else(|e| e, |v| v + 1) as i32
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1800-1899/1894.Find the Student that Will Replace the Chalk/README_EN.md

@@ -132,6 +132,27 @@ func chalkReplacer(chalk []int, k int) int {
 }
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn chalk_replacer(chalk: Vec<i32>, k: i32) -> i32 {
+        let pre_sum: Vec<i64> = chalk
+            .into_iter()
+            .map(|x| x as i64)
+            .scan(0, |state, x| {
+                *state += x;
+                Some(*state)
+            })
+            .collect();
+
+        pre_sum
+            .binary_search(&(k as i64 % pre_sum.last().unwrap()))
+            .map_or_else(|e| e, |v| v + 1) as i32
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1800-1899/1894.Find the Student that Will Replace the Chalk/Solution.rs

@@ -0,0 +1,16 @@
+impl Solution {
+    pub fn chalk_replacer(chalk: Vec<i32>, k: i32) -> i32 {
+        let pre_sum: Vec<i64> = chalk
+            .into_iter()
+            .map(|x| x as i64)
+            .scan(0, |state, x| {
+                *state += x;
+                Some(*state)
+            })
+            .collect();
+
+        pre_sum
+            .binary_search(&(k as i64 % pre_sum.last().unwrap()))
+            .map_or_else(|e| e, |v| v + 1) as i32
+    }
+}