From c4a4a0323127f3b47e89fdeefd7bc8a57d404e1e Mon Sep 17 00:00:00 2001 From: Effy Wang Date: Fri, 1 Apr 2022 17:26:47 +0800 Subject: [PATCH 1/4] =?UTF-8?q?Update=200704.=E4=BA=8C=E5=88=86=E6=9F=A5?= =?UTF-8?q?=E6=89=BE.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit add detailed comments to the Javascript version of Binary Search --- problems/0704.二分查找.md | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/problems/0704.二分查找.md b/problems/0704.二分查找.md index 15e096a0..55625130 100644 --- a/problems/0704.二分查找.md +++ b/problems/0704.二分查找.md @@ -276,7 +276,7 @@ func search(nums []int, target int) int { ``` **JavaScript:** -（版本一）左闭右闭区间 +（版本一）左闭右闭区间 [left, right] ```js /** @@ -285,10 +285,12 @@ func search(nums []int, target int) int { * @return {number} */ var search = function(nums, target) { + // right是数组最后一个数的下标，num[right]在查找范围内，是左闭右闭区间 let left = 0, right = nums.length - 1; - // 使用左闭右闭区间 + // 当left=right时，由于nums[right]在查找范围内，所以要包括此情况 while (left <= right) { let mid = left + Math.floor((right - left)/2); + // 如果中间数大于目标值，要把中间数排除查找范围，所以右边界更新为mid-1；如果右边界更新为mid，那中间数还在下次查找范围内 if (nums[mid] > target) { right = mid - 1; // 去左面闭区间寻找 } else if (nums[mid] < target) { @@ -300,7 +302,7 @@ var search = function(nums, target) { return -1; }; ``` -（版本二）左闭右开区间 +（版本二）左闭右开区间 [left, right) ```js /** @@ -309,10 +311,13 @@ var search = function(nums, target) { * @return {number} */ var search = function(nums, target) { - let left = 0, right = nums.length; - // 使用左闭右开区间 [left, right) + // right是数组最后一个数的下标+1，nums[right]不在查找范围内，是左闭右开区间 + let left = 0, right = nums.length; + // 当left=right时，由于nums[right]不在查找范围，所以不必包括此情况 while (left < right) { let mid = left + Math.floor((right - left)/2); + // 如果中间值大于目标值，中间值不应在下次查找的范围内，但中间值的前一个值应在； + // 由于right本来就不在查找范围内，所以将右边界更新为中间值，如果更新右边界为mid-1则将中间值的前一个值也踢出了下次寻找范围 if (nums[mid] > target) { right = mid; // 去左区间寻找 } else if (nums[mid] < target) { From 3f7dd67a8031663d2b673a41587e3a640e0a4b1f Mon Sep 17 00:00:00 2001 From: FrankLin Date: Fri, 1 Apr 2022 10:57:25 -0400 Subject: [PATCH 2/4] Add C version for LeetCode349 using array --- problems/0349.两个数组的交集.md | 32 ++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/problems/0349.两个数组的交集.md b/problems/0349.两个数组的交集.md index 82be1829..64d80a37 100644 --- a/problems/0349.两个数组的交集.md +++ b/problems/0349.两个数组的交集.md @@ -281,6 +281,38 @@ impl Solution { } } ``` + +C: +```C +int* intersection1(int* nums1, int nums1Size, int* nums2, int nums2Size, int* returnSize){ + + int nums1Cnt[1000] = {0}; + int lessSize = nums1Size < nums2Size ? nums1Size : nums2Size; + int * result = (int *) calloc(lessSize, sizeof(int)); + int resultIndex = 0; + int* tempNums; + + int i; + + //Calculate the number's counts for nums1 array + for(i = 0; i < nums1Size; i ++) { + nums1Cnt[nums1[i]]++; + } + + //Check if the value existing in nums1 count array + for(i = 0; i < nums2Size; i ++) { + if(nums1Cnt[nums2[i]] > 0) { + result[resultIndex] = nums2[i]; + resultIndex ++; + //Clear this count to avoid duplicated value + nums1Cnt[nums2[i]] = 0; + } + } + * returnSize = resultIndex; + return result; +} +``` + ## 相关题目 * 350.两个数组的交集 II From abc08b6bb6f698135efe52ad0a7f20b333d32173 Mon Sep 17 00:00:00 2001 From: FrankLin Date: Fri, 1 Apr 2022 11:01:00 -0400 Subject: [PATCH 3/4] correct comments of C version of Leetcode349 --- problems/0349.两个数组的交集.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/problems/0349.两个数组的交集.md b/problems/0349.两个数组的交集.md index 64d80a37..45f19b6e 100644 --- a/problems/0349.两个数组的交集.md +++ b/problems/0349.两个数组的交集.md @@ -294,17 +294,17 @@ int* intersection1(int* nums1, int nums1Size, int* nums2, int nums2Size, int* re int i; - //Calculate the number's counts for nums1 array + /* Calculate the number's counts for nums1 array */ for(i = 0; i < nums1Size; i ++) { nums1Cnt[nums1[i]]++; } - //Check if the value existing in nums1 count array + /* Check if the value in nums2 is existing in nums1 count array */ for(i = 0; i < nums2Size; i ++) { if(nums1Cnt[nums2[i]] > 0) { result[resultIndex] = nums2[i]; resultIndex ++; - //Clear this count to avoid duplicated value + /* Clear this count to avoid duplicated value */ nums1Cnt[nums2[i]] = 0; } } From 297a22fd880f207bd9b621b7dbd5e8dfd84340a1 Mon Sep 17 00:00:00 2001 From: FrankLin Date: Fri, 1 Apr 2022 15:11:00 -0400 Subject: [PATCH 4/4] Add C version for Leetcode202 passed Leetcode submission --- problems/0202.快乐数.md | 70 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) diff --git a/problems/0202.快乐数.md b/problems/0202.快乐数.md index f0a46a40..741a735a 100644 --- a/problems/0202.快乐数.md +++ b/problems/0202.快乐数.md @@ -315,5 +315,75 @@ class Solution { } ``` +C: +```C +typedef struct HashNodeTag { + int key; /* num */ + struct HashNodeTag *next; +}HashNode; + +/* Calcualte the hash key */ +static inline int hash(int key, int size) { + int index = key % size; + return (index > 0) ? (index) : (-index); +} + +/* Calculate the sum of the squares of its digits*/ +static inline int calcSquareSum(int num) { + unsigned int sum = 0; + while(num > 0) { + sum += (num % 10) * (num % 10); + num = num/10; + } + return sum; +} + +#define HASH_TABLE_SIZE (32) + +bool isHappy(int n){ + int sum = n; + int index = 0; + bool bHappy = false; + bool bExit = false; + /* allocate the memory for hash table with chaining method*/ + HashNode ** hashTable = (HashNode **)calloc(HASH_TABLE_SIZE, sizeof(HashNode)); + + while(bExit == false) { + /* check if n has been calculated */ + index = hash(n, HASH_TABLE_SIZE); + + HashNode ** p = hashTable + index; + + while((*p) && (bExit == false)) { + /* Check if this num was calculated, if yes, this will be endless loop */ + if((*p)->key == n) { + bHappy = false; + bExit = true; + } + /* move to next node of the same index */ + p = &((*p)->next); + } + + /* put n intot hash table */ + HashNode * newNode = (HashNode *)malloc(sizeof(HashNode)); + newNode->key = n; + newNode->next = NULL; + + *p = newNode; + + sum = calcSquareSum(n); + if(sum == 1) { + bHappy = true; + bExit = true; + } + else { + n = sum; + + } + } + + return bHappy; +} +``` -----------------------