Add more algorithm solutions for leetcode

leetcode/README.md

@@ -6,6 +6,16 @@ LeetCode
 
 | # | Title | Solution | Difficulty |
 |---| ----- | -------- | ---------- |
+|26|[Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/) | [C](./src/26.c)|Easy|
 |35|[Search Insert Position](https://leetcode.com/problems/search-insert-position/) | [C](./src/35.c)|Easy|
-|704|[Search Insert Position](https://leetcode.com/problems/binary-search/) | [C](./src/704.c)|Easy|
+|125|[Valid Palindrome](https://leetcode.com/problems/valid-palindrome/) | [C](./src/125.c)|Easy|
+|217|[Contains Duplicate](https://leetcode.com/problems/contains-duplicate/) | [C](./src/217.c)|Easy|
+|344|[Reverse String](https://leetcode.com/problems/reverse-string/) | [C](./src/344.c)|Easy|
+|387|[First Unique Character in a String](https://leetcode.com/problems/first-unique-character-in-a-string/) | [C](./src/387.c)|Easy|
+|442|[Find All Duplicates in an Array](https://leetcode.com/problems/find-all-duplicates-in-an-array/) | [C](./src/442.c)|Medium|
+|520|[Detect Capital](https://leetcode.com/problems/detect-capital/) | [C](./src/520.c)|Easy|
+|561|[Array Partition I](https://leetcode.com/problems/array-partition-i/) | [C](./src/561.c)|Easy|
+|704|[Binary Search](https://leetcode.com/problems/binary-search/) | [C](./src/704.c)|Easy|
+|709|[To Lower Case](https://leetcode.com/problems/to-lower-case/) | [C](./src/709.c)|Easy|
 |905|[Sort Array By Parity](https://leetcode.com/problems/sort-array-by-parity/) | [C](./src/905.c)|Easy|
+|917|[Reverse Only Letters](https://leetcode.com/problems/reverse-only-letters/) | [C](./src/917.c)|Easy|

leetcode/src/125.c

@@ -0,0 +1,19 @@
+bool isPalindrome(char * s){
+    int start = 0, end = strlen(s) - 1;
+    while(start < end) {
+        if (!isalpha(s[start]) && !isalnum(s[start])) {
+            start++;
+        }
+        else if (!isalpha(s[end]) && !isalnum(s[end])) {
+            end--;
+        } else {
+            char c1 = tolower(s[start]);
+            char c2 = tolower(s[end]);
+            if(c1 != c2)
+                return 0;
+            start++;
+            end--;
+        }
+    }
+    return 1;
+}

leetcode/src/217.c

@@ -0,0 +1,13 @@
+int numcmp(const void *a, const void *b) {
+    return *(int *)a - *(int *)b;
+}
+
+bool containsDuplicate(int* nums, int numsSize){
+    int i;
+    qsort(nums, numsSize, sizeof(int), numcmp);
+    for (i = 0; i < numsSize - 1; i++) {
+        if(nums[i] == nums[i+1])
+            return 1;
+    }
+    return 0;
+}

leetcode/src/26.c

@@ -0,0 +1,10 @@
+int removeDuplicates(int* nums, int numsSize){
+    int count = 0, i;
+    for (i = 1; i < numsSize; i++) {
+        if (nums[i] == nums[i-1])
+            count++;
+        else
+            nums[i-count] = nums[i];
+    }
+    return numsSize - count;
+}

leetcode/src/344.c

@@ -0,0 +1,10 @@
+void reverseString(char* s, int sSize){
+    int last = sSize - 1, i;
+    for (i = 0; i < last; i++) {
+        char tmp = s[i];
+        s[i] = s[last];
+        s[last] = tmp;
+        last--;
+    }
+
+}

leetcode/src/387.c

@@ -0,0 +1,11 @@
+int firstUniqChar(char * s){
+    int *arr = calloc(256, sizeof(int));
+    int i;
+    for(i = 0; i < strlen(s); i++)
+        arr[s[i]] = arr[s[i]] + 1;
+    for(i = 0; i < strlen(s); i++) {
+        if(arr[s[i]] == 1)
+            return i;
+    }
+    return -1;
+}

leetcode/src/442.c

@@ -0,0 +1,21 @@
+int cmpval (const void *a, const void *b) {
+    return *(int *)a - *(int *)b;
+}
+
+int* findDuplicates(int* nums, int numsSize, int* returnSize){
+
+    int i;
+    qsort(nums, numsSize, sizeof(int), cmpval);
+    int *retArr = malloc(numsSize * sizeof(int));
+    *returnSize = 0;
+    for (i = 0; i < numsSize - 1;) {
+        if (nums[i] == nums[i + 1]) {\
+            retArr[*returnSize] = nums[i];
+            *returnSize = *returnSize + 1;
+            i = i + 2;
+        } else {
+            i = i + 1;
+        }
+    }
+    return retArr;
+}

leetcode/src/520.c

@@ -0,0 +1,39 @@
+bool detectCapitalUse(char * word){
+    int len = strlen(word);
+    if(len == 1)
+        return 1;
+    int countUpper = 0, i;
+    for(i = 0; i < len; i++) {
+        if(isupper(word[i]))
+            countUpper++;
+    }
+    /* All lower case */
+    if (countUpper == 0)
+        return 1;
+    /* 1st character is upper, and the rest is lower case */
+    if (countUpper == 1 && isupper(word[0]))
+        return 1;
+    /* Check all character is upper case? */
+    else
+        return countUpper == len;
+}
+
+/* Another way */
+bool isAllUpper(char *word) {
+    int len = strlen(word);
+    for(int i = 0; i < len; i++) {
+        if(islower(word[i]))
+            return 0;
+    }
+    return 1;
+}
+bool detectCapitalUse(char * word){
+    int len = strlen(word);
+    for(int i = 1; i < len; i++) {
+        if(isupper(word[i]) && !isAllUpper(word))
+            return 0;
+    }
+    return 1;
+}
+
+

leetcode/src/561.c

@@ -0,0 +1,10 @@
+int cmpval (const void *a, const void *b) {
+    return *(int *)a - *(int *)b;
+}
+int arrayPairSum(int* nums, int numsSize){
+    int sum = 0, i;
+    qsort(nums, numsSize, sizeof(int), cmpval);
+    for(i = 0; i < numsSize; i = i + 2)
+        sum = sum + nums[i];
+    return sum;
+}

leetcode/src/709.c

@@ -0,0 +1,5 @@
+char * toLowerCase(char * str){
+    for (int i = 0; i< strlen(str); i++)
+        str[i] = tolower(str[i]);
+    return str;
+}

leetcode/src/917.c

@@ -0,0 +1,20 @@
+char * reverseOnlyLetters(char * S){
+    int last = strlen(S) - 1, i;
+    for(i = 0; i < last;) {
+        if(!isalpha(S[i])) {
+            i++;
+            continue;
+        }
+        if(!isalpha(S[last])) {
+            last--;
+            continue;
+        }
+        char tmp = S[i];
+        S[i] = S[last];
+        S[last] = tmp;
+        i++;
+        last--;
+    }
+    return S;
+}
+