added new C programs, moved misplaced files

problems/closed-loops/closed-loops.c

@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAX_LEN 100
+
+int main()
+{
+ int x, y;
+ int loops = 0;
+ char s[MAX_LEN];
+ char *p;
+ printf("Enter number to count loops: ");
+ scanf("%d", &x);
+ y = x;
+
+ sprintf(s, "%d", x);
+ p = s;
+ while (*p != '\0')
+ {
+ if (*p == '6')
+ loops++;
+ else if (*p == '8')
+ loops += 2;
+ else if (*p == '9')
+ loops++;
+ else if (*p == '0')
+ loops++;
+ p++;
+ }
+ printf("%d has %d loops\n", y, loops);
+ return 0;
+}

problems/duplicate-element/duplicate-element.cpp

@@ -0,0 +1,79 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+int bruteforce(std::vector<int> list);
+int hash(std::vector<int> list);
+bool mysort(int i, int j);
+int sortthencompare(std::vector<int> list);
+int binarysearch(std::vector<int> list, int n, int m);
+
+int bruteforce(std::vector<int> list)
+{
+ for (auto i = 0; i < list.size(); i++)
+ {
+ for (auto j = i+1; j < list.size(); j++)
+ {
+ if (list[i] == list[j])
+ return list[i];
+ }
+ }
+ return -1;
+}
+
+int hash(std::vector<int> list)
+{
+ std::vector<bool> found = {false};
+ for (auto i = 0; i < list.size(); i++)
+ {
+ if (found[list[i]])
+ return list[i];
+ found[list[i]] = true;
+ }
+ return -1;
+}
+
+bool mysort(int i, int j)
+{
+ return i < j;
+}
+
+int sortthencompare(std::vector<int> list)
+{
+ std::stable_sort(list.begin(), list.end(), mysort);
+ for (auto i = 0; i < list.size(); i++)
+ {
+ if (list[i] == list[i+1])
+ return list[i];
+ }
+ return -1;
+}
+
+int binarysearch(std::vector<int> list, int n, int m)
+{
+ while (n < m)
+ {
+ int count = 0;
+ int mid = (n + m) / 2;
+ for (int item : list)
+ if (item >= n && item <= mid)
+ count++;
+ if (count > mid - n + 1)
+ m = mid;
+ else
+ n = mid + 1;
+ }
+ return m;
+}
+
+int main()
+{
+ std::vector<int> list = {9, 8, 6, 7, 5, 7, 3, 4, 2, 1};
+ std::cout << "Expected result: 7" << std::endl;
+ std::cout << "Brute force: " << bruteforce(list) << std::endl;
+ std::cout << "Using hash: " << hash(list) << std::endl;
+ std::cout << "Sort then compare: " << sortthencompare(list) << std::endl;
+ std::cout << "Binary search: " << binarysearch(list, 1, list.size() - 1) 
+ << std::endl;
+ return 0;
+}

problems/factorial/factorial.hs

@@ -0,0 +1,4 @@
+factorial :: Integer -> Integer
+factorial 0 = 1;
+factorial 1 = 1;
+factorial x = x * factorial (x - 1)

problems/reverse-string/reverse-string.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+
+#define MAX_LEN 100
+
+void reverse(char *message);
+
+int main(void) {
+
+ char message[MAX_LEN];
+ char c, *p = message;
+
+ printf("Enter a message: ");
+
+ while ((c = getchar()) != '\n' && p < message + MAX_LEN)
+ *p++ = c;
+ *p = '\0';
+
+ reverse(message);
+ printf("Reversal is: ");
+
+ printf("%s\n", message);
+
+ return 0;
+} 
+
+void reverse(char *message) {
+
+ char *p = message, *q = message, temp;
+
+ while (*q)
+ q++;
+ q--;
+
+ while (p < q) {
+ temp = *p;
+ *p = *q;
+ *q = temp;
+ p++;
+ q--;
+ }
+}