feat: add solutions to lc problem: No.1700. Number of Studnets Unable to Eat Lunch

Author: yanglbme

solution/1700-1799/1700.Number of Students Unable to Eat Lunch/README.md

@@ -53,27 +53,51 @@
 	<li><code>students[i]</code> 要么是 <code>0</code> ，要么是 <code>1</code> 。</li>
 </ul>
 
-
 ## 解法
 
 <!-- 这里可写通用的实现逻辑 -->
 
+学生位置可调整，而三明治位置不可调整。也就是说，若前面的三明治没被拿走，则往后的所有三明治也无法被拿走。
+
+因此，先用计数器 counter 统计学生喜欢的三明治种类和对应的数量，然后遍历三明治，若在 counter 中找不到喜欢此三明治的学生，说明已经找到答案，当前以及往后的三明治均无法被拿走，数量为 `n - i`。
+
 <!-- tabs:start -->
 
 ### **Python3**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
-
+class Solution:
+    def countStudents(self, students: List[int], sandwiches: List[int]) -> int:
+        counter = collections.Counter(students)
+        for i, sandwich in enumerate(sandwiches):
+            if counter[sandwich] == 0:
+                return len(students) - i
+            counter[sandwich] -= 1
+        return 0
 ```
 
 ### **Java**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
-
+class Solution {
+    public int countStudents(int[] students, int[] sandwiches) {
+        int[] counter = new int[2];
+        for (int i : students) {
+            counter[i] += 1;
+        }
+        for (int i = 0; i < sandwiches.length; ++i) {
+            if (counter[sandwiches[i]] == 0) {
+                return sandwiches.length - i;
+            }
+            counter[sandwiches[i]] -= 1;
+        }
+        return 0;
+    }
+}
 ```
 
 ### **...**

solution/1700-1799/1700.Number of Students Unable to Eat Lunch/README_EN.md

@@ -52,21 +52,41 @@ Hence all students are able to eat.
 	<li><code>students[i]</code> is <code>0</code> or <code>1</code>.</li>
 </ul>
 
-
 ## Solutions
 
 <!-- tabs:start -->
 
 ### **Python3**
 
 ```python
-
+class Solution:
+    def countStudents(self, students: List[int], sandwiches: List[int]) -> int:
+        counter = collections.Counter(students)
+        for i, sandwich in enumerate(sandwiches):
+            if counter[sandwich] == 0:
+                return len(students) - i
+            counter[sandwich] -= 1
+        return 0
 ```
 
 ### **Java**
 
 ```java
-
+class Solution {
+    public int countStudents(int[] students, int[] sandwiches) {
+        int[] counter = new int[2];
+        for (int i : students) {
+            counter[i] += 1;
+        }
+        for (int i = 0; i < sandwiches.length; ++i) {
+            if (counter[sandwiches[i]] == 0) {
+                return sandwiches.length - i;
+            }
+            counter[sandwiches[i]] -= 1;
+        }
+        return 0;
+    }
+}
 ```
 
 ### **...**

solution/1700-1799/1700.Number of Students Unable to Eat Lunch/Solution.java

@@ -0,0 +1,15 @@
+class Solution {
+    public int countStudents(int[] students, int[] sandwiches) {
+        int[] counter = new int[2];
+        for (int i : students) {
+            counter[i] += 1;
+        }
+        for (int i = 0; i < sandwiches.length; ++i) {
+            if (counter[sandwiches[i]] == 0) {
+                return sandwiches.length - i;
+            }
+            counter[sandwiches[i]] -= 1;
+        }
+        return 0;
+    }
+}

solution/1700-1799/1700.Number of Students Unable to Eat Lunch/Solution.py

@@ -0,0 +1,8 @@
+class Solution:
+    def countStudents(self, students: List[int], sandwiches: List[int]) -> int:
+        counter = collections.Counter(students)
+        for i, sandwich in enumerate(sandwiches):
+            if counter[sandwich] == 0:
+                return len(students) - i
+            counter[sandwich] -= 1
+        return 0

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

@@ -68,6 +68,8 @@
 
 二分法。
 
+以“二分法”方式枚举速度值，找到满足条件的最小速度。
+
 <!-- tabs:start -->
 
 ### **Python3**
@@ -104,7 +106,7 @@ class Solution {
         if (dist.length - 1 >= hour) {
             return -1;
         }
-        int l = 0, r = 10000000;
+        int l = 1, r = 10000000;
         while (l < r) {
             int m = (l + r) >> 1;
             if (arriveOnTime(dist, m, hour)) {

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

@@ -94,7 +94,7 @@ class Solution {
         if (dist.length - 1 >= hour) {
             return -1;
         }
-        int l = 0, r = 10000000;
+        int l = 1, r = 10000000;
         while (l < r) {
             int m = (l + r) >> 1;
             if (arriveOnTime(dist, m, hour)) {

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

@@ -3,7 +3,7 @@ public int minSpeedOnTime(int[] dist, double hour) {
         if (dist.length - 1 >= hour) {
             return -1;
         }
-        int l = 0, r = 10000000;
+        int l = 1, r = 10000000;
         while (l < r) {
             int m = (l + r) >> 1;
             if (arriveOnTime(dist, m, hour)) {