add 1394

Author: luliyucoordinate

README.md

@@ -691,4 +691,5 @@ LeetCode
 |1389|[Create Target Array in the Given Order](https://leetcode.com/problems/create-target-array-in-the-given-order/)|c|[c++](./src/1389-Create-Target-Array-in-the-Given-Order/1389.cpp)|[python](./src/1389-Create-Target-Array-in-the-Given-Order/1389.py)|[go](./src/1389-Create-Target-Array-in-the-Given-Order/1389.go)|[js](./src/1389-Create-Target-Array-in-the-Given-Order/1389.js)|[java](./src/1389-Create-Target-Array-in-the-Given-Order/1389.java)|Easy|
 |1390|[Four Divisors](https://leetcode.com/problems/four-divisors/)|c|[c++](./src/1390-Four-Divisors/1390.cpp)|[python](./src/1390-Four-Divisors/1390.py)|[go](./src/1390-Four-Divisors/1390.go)|[js](./src/1390-Four-Divisors/1390.js)|[java](./src/1390-Four-Divisors/1390.java)|Medium|
 |1391|[Check if There is a Valid Path in a Grid](https://leetcode.com/problems/check-if-there-is-a-valid-path-in-a-grid/)|c|[c++](./src/1391-Check-if-There-is-a-Valid-Path-in-a-Grid/1391.cpp)|[python](./src/1391-Check-if-There-is-a-Valid-Path-in-a-Grid/1391.py)|[go](./src/1391-Check-if-There-is-a-Valid-Path-in-a-Grid/1391.go)|[js](./src/1391-Check-if-There-is-a-Valid-Path-in-a-Grid/1391.js)|[java](./src/1391-Check-if-There-is-a-Valid-Path-in-a-Grid/1391.java)|Medium|
-|1392|[Longest Happy Prefix](https://leetcode.com/problems/longest-happy-prefix/)|c|[c++](./src/1392-Longest-Happy-Prefix/1392.cpp)|[python](./src/1392-Longest-Happy-Prefix/1392.py)|[go](./src/1392-Longest-Happy-Prefix/1392.go)|[js](./src/1392-Longest-Happy-Prefix/1392.js)|[java](./src/1392-Longest-Happy-Prefix/1392.java)|Hard|
+|1392|[Longest Happy Prefix](https://leetcode.com/problems/longest-happy-prefix/)|c|[c++](./src/1392-Longest-Happy-Prefix/1392.cpp)|[python](./src/1392-Longest-Happy-Prefix/1392.py)|[go](./src/1392-Longest-Happy-Prefix/1392.go)|[js](./src/1392-Longest-Happy-Prefix/1392.js)|[java](./src/1392-Longest-Happy-Prefix/1392.java)|Hard|
+|1394|[Find Lucky Integer in an Array](https://leetcode.com/problems/find-lucky-integer-in-an-array/)|c|[c++](./src/1394-Find-Lucky-Integer-in-an-Array/1394.cpp)|[python](./src/1394-Find-Lucky-Integer-in-an-Array/1394.py)|[go](./src/1394-Find-Lucky-Integer-in-an-Array/1394.go)|[js](./src/1394-Find-Lucky-Integer-in-an-Array/1394.js)|[java](./src/1394-Find-Lucky-Integer-in-an-Array/1394.java)|Easy|

src/1394-Find-Lucky-Integer-in-an-Array/1394.cpp

@@ -0,0 +1,12 @@
+class Solution {
+public:
+    int findLucky(vector<int>& arr) {
+        int cnt[501] = {};
+        for (int i : arr) cnt[i]++;
+        
+        for (int i = 500; i; i--) {
+            if (cnt[i] == i) return i;
+        }
+        return -1;
+    }
+};

src/1394-Find-Lucky-Integer-in-an-Array/1394.go

@@ -0,0 +1,13 @@
+func findLucky(arr []int) int {
+    cnt := make([]int, 501)
+    for _, i := range arr {
+        cnt[i]++
+    }
+    
+    for i := 500; i > 0; i-- {
+        if cnt[i] == i {
+            return i
+        }
+    }
+    return -1
+}

src/1394-Find-Lucky-Integer-in-an-Array/1394.java

@@ -0,0 +1,11 @@
+class Solution {
+    public int findLucky(int[] arr) {
+        int[] cnt = new int[501];
+        for (int i : arr) cnt[i]++;
+        
+        for (int i = 500; i > 0; i--) {
+            if (cnt[i] == i) return i;
+        }
+        return -1;
+    }
+}

src/1394-Find-Lucky-Integer-in-an-Array/1394.js

@@ -0,0 +1,9 @@
+var findLucky = function(arr) {
+    let cnt = new Array(501).fill(0);
+    for (let i of arr) cnt[i]++;
+
+    for (let i = 500; i > 0; i--) {
+        if (cnt[i] == i) return i;
+    }
+    return -1;
+};

src/1394-Find-Lucky-Integer-in-an-Array/1394.py

@@ -0,0 +1,3 @@
+class Solution:
+    def findLucky(self, arr: List[int]) -> int:
+        return max([k for k, v in collections.Counter(arr).items() if k == v] + [-1])

src/addProb.py

@@ -2,10 +2,10 @@
 import os, bisect
 
 # 题目名称
-name = "Short Encoding of Words"
-ID = 820
-url = "https://leetcode.com/problems/short-encoding-of-words/"
-difficult = "Medium"
+name = "Find Lucky Integer in an Array"
+ID = 1394 
+url = "https://leetcode.com/problems/find-lucky-integer-in-an-array/"
+difficult = "Easy"
 prog = ['c', 'cpp', 'py', 'go', 'js', 'java']