feat: add solutions to lc problem: No.0853

solution/0800-0899/0853.Car Fleet/README.md

@@ -66,22 +66,128 @@
 
 <!-- 这里可写通用的实现逻辑 -->
 
+**方法一：排序**
+
+我们将车辆按照位置降序排序，这样我们只需要比较相邻两辆车的到达时间即可。
+
+我们初始化一个变量 $pre$ 表示上一辆车到达终点的时间，如果当前车辆到达终点的时间大于 $pre$，说明当前车辆无法追上前面的车辆，因此需要另外开一个车队，否则当前车辆会与前面的车辆组成一个车队。
+
+时间复杂度 $O(n)$，空间复杂度 $O(n)$。其中 $n$ 是车辆的数量。
+
 <!-- tabs:start -->
 
 ### **Python3**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
-
+class Solution:
+    def carFleet(self, target: int, position: List[int], speed: List[int]) -> int:
+        idx = sorted(range(len(position)), key=lambda i: position[i])
+        ans = pre = 0
+        for i in idx[::-1]:
+            t = (target - position[i]) / speed[i]
+            if t > pre:
+                ans += 1
+                pre = t
+        return ans
 ```
 
 ### **Java**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
+class Solution {
+    public int carFleet(int target, int[] position, int[] speed) {
+        int n = position.length;
+        Integer[] idx = new Integer[n];
+        for (int i = 0; i < n; ++i) {
+            idx[i] = i;
+        }
+        Arrays.sort(idx, (i, j) -> position[j] - position[i]);
+        int ans = 0;
+        double pre = 0;
+        for (int i : idx) {
+            double t = 1.0 * (target - position[i]) / speed[i];
+            if (t > pre) {
+                ++ans;
+                pre = t;
+            }
+        }
+        return ans;
+    }
+}
+```
+
+### **C++**
+
+```cpp
+class Solution {
+public:
+    int carFleet(int target, vector<int>& position, vector<int>& speed) {
+        int n = position.size();
+        vector<int> idx(n);
+        iota(idx.begin(), idx.end(), 0);
+        sort(idx.begin(), idx.end(), [&](int i, int j) {
+            return position[i] > position[j];
+        });
+        int ans = 0;
+        double pre = 0;
+        for (int i : idx) {
+            double t = 1.0 * (target - position[i]) / speed[i];
+            if (t > pre) {
+                ++ans;
+                pre = t;
+            }
+        }
+        return ans;
+    }
+};
+```
+
+### **Go**
+
+```go
+func carFleet(target int, position []int, speed []int) (ans int) {
+	n := len(position)
+	idx := make([]int, n)
+	for i := range idx {
+		idx[i] = i
+	}
+	sort.Slice(idx, func(i, j int) bool { return position[idx[j]] < position[idx[i]] })
+	var pre float64
+	for _, i := range idx {
+		t := float64(target-position[i]) / float64(speed[i])
+		if t > pre {
+			ans++
+			pre = t
+		}
+	}
+	return
+}
+```
 
+### **TypeScript**
+
+```ts
+function carFleet(target: number, position: number[], speed: number[]): number {
+    const n = position.length;
+    const idx = Array(n)
+        .fill(0)
+        .map((_, i) => i)
+        .sort((i, j) => position[j] - position[i]);
+    let ans = 0;
+    let pre = 0;
+    for (const i of idx) {
+        const t = (target - position[i]) / speed[i];
+        if (t > pre) {
+            ++ans;
+            pre = t;
+        }
+    }
+    return ans;
+}
 ```
 
 ### **...**

solution/0800-0899/0853.Car Fleet/README_EN.md

@@ -66,13 +66,111 @@ Then, the fleet (speed 2) and the car starting at 4 (speed 1) become one fleet,
 ### **Python3**
 
 ```python
-
+class Solution:
+    def carFleet(self, target: int, position: List[int], speed: List[int]) -> int:
+        idx = sorted(range(len(position)), key=lambda i: position[i])
+        ans = pre = 0
+        for i in idx[::-1]:
+            t = (target - position[i]) / speed[i]
+            if t > pre:
+                ans += 1
+                pre = t
+        return ans
 ```
 
 ### **Java**
 
 ```java
+class Solution {
+    public int carFleet(int target, int[] position, int[] speed) {
+        int n = position.length;
+        Integer[] idx = new Integer[n];
+        for (int i = 0; i < n; ++i) {
+            idx[i] = i;
+        }
+        Arrays.sort(idx, (i, j) -> position[j] - position[i]);
+        int ans = 0;
+        double pre = 0;
+        for (int i : idx) {
+            double t = 1.0 * (target - position[i]) / speed[i];
+            if (t > pre) {
+                ++ans;
+                pre = t;
+            }
+        }
+        return ans;
+    }
+}
+```
+
+### **C++**
+
+```cpp
+class Solution {
+public:
+    int carFleet(int target, vector<int>& position, vector<int>& speed) {
+        int n = position.size();
+        vector<int> idx(n);
+        iota(idx.begin(), idx.end(), 0);
+        sort(idx.begin(), idx.end(), [&](int i, int j) {
+            return position[i] > position[j];
+        });
+        int ans = 0;
+        double pre = 0;
+        for (int i : idx) {
+            double t = 1.0 * (target - position[i]) / speed[i];
+            if (t > pre) {
+                ++ans;
+                pre = t;
+            }
+        }
+        return ans;
+    }
+};
+```
+
+### **Go**
+
+```go
+func carFleet(target int, position []int, speed []int) (ans int) {
+	n := len(position)
+	idx := make([]int, n)
+	for i := range idx {
+		idx[i] = i
+	}
+	sort.Slice(idx, func(i, j int) bool { return position[idx[j]] < position[idx[i]] })
+	var pre float64
+	for _, i := range idx {
+		t := float64(target-position[i]) / float64(speed[i])
+		if t > pre {
+			ans++
+			pre = t
+		}
+	}
+	return
+}
+```
 
+### **TypeScript**
+
+```ts
+function carFleet(target: number, position: number[], speed: number[]): number {
+    const n = position.length;
+    const idx = Array(n)
+        .fill(0)
+        .map((_, i) => i)
+        .sort((i, j) => position[j] - position[i]);
+    let ans = 0;
+    let pre = 0;
+    for (const i of idx) {
+        const t = (target - position[i]) / speed[i];
+        if (t > pre) {
+            ++ans;
+            pre = t;
+        }
+    }
+    return ans;
+}
 ```
 
 ### **...**

solution/0800-0899/0853.Car Fleet/Solution.cpp

@@ -0,0 +1,21 @@
+class Solution {
+public:
+    int carFleet(int target, vector<int>& position, vector<int>& speed) {
+        int n = position.size();
+        vector<int> idx(n);
+        iota(idx.begin(), idx.end(), 0);
+        sort(idx.begin(), idx.end(), [&](int i, int j) {
+            return position[i] > position[j];
+        });
+        int ans = 0;
+        double pre = 0;
+        for (int i : idx) {
+            double t = 1.0 * (target - position[i]) / speed[i];
+            if (t > pre) {
+                ++ans;
+                pre = t;
+            }
+        }
+        return ans;
+    }
+};

solution/0800-0899/0853.Car Fleet/Solution.go

@@ -0,0 +1,17 @@
+func carFleet(target int, position []int, speed []int) (ans int) {
+	n := len(position)
+	idx := make([]int, n)
+	for i := range idx {
+		idx[i] = i
+	}
+	sort.Slice(idx, func(i, j int) bool { return position[idx[j]] < position[idx[i]] })
+	var pre float64
+	for _, i := range idx {
+		t := float64(target-position[i]) / float64(speed[i])
+		if t > pre {
+			ans++
+			pre = t
+		}
+	}
+	return
+}

solution/0800-0899/0853.Car Fleet/Solution.java

@@ -0,0 +1,20 @@
+class Solution {
+    public int carFleet(int target, int[] position, int[] speed) {
+        int n = position.length;
+        Integer[] idx = new Integer[n];
+        for (int i = 0; i < n; ++i) {
+            idx[i] = i;
+        }
+        Arrays.sort(idx, (i, j) -> position[j] - position[i]);
+        int ans = 0;
+        double pre = 0;
+        for (int i : idx) {
+            double t = 1.0 * (target - position[i]) / speed[i];
+            if (t > pre) {
+                ++ans;
+                pre = t;
+            }
+        }
+        return ans;
+    }
+}

solution/0800-0899/0853.Car Fleet/Solution.py

@@ -1,19 +1,10 @@
-class Solution:
-    def carFleet(self, target, position, speed):
-        """
-        :type target: int
-        :type position: List[int]
-        :type speed: List[int]
-        :rtype: int
-        """
-        car = [(pos, spe) for pos, spe in zip(position, speed)]
-        car.sort(reverse=True)
-        time = [(target - pos) / spe for pos, spe in car]
-        ls = []
-        for i in time:
-            if not ls:
-                ls.append(i)
-            else:
-                if i > ls[-1]:
-                    ls.append(i)
-        return len(ls)
+class Solution:
+    def carFleet(self, target: int, position: List[int], speed: List[int]) -> int:
+        idx = sorted(range(len(position)), key=lambda i: position[i])
+        ans = pre = 0
+        for i in idx[::-1]:
+            t = (target - position[i]) / speed[i]
+            if t > pre:
+                ans += 1
+                pre = t
+        return ans

solution/0800-0899/0853.Car Fleet/Solution.ts

@@ -0,0 +1,17 @@
+function carFleet(target: number, position: number[], speed: number[]): number {
+    const n = position.length;
+    const idx = Array(n)
+        .fill(0)
+        .map((_, i) => i)
+        .sort((i, j) => position[j] - position[i]);
+    let ans = 0;
+    let pre = 0;
+    for (const i of idx) {
+        const t = (target - position[i]) / speed[i];
+        if (t > pre) {
+            ++ans;
+            pre = t;
+        }
+    }
+    return ans;
+}