Problem done with some speedy C

problems/27/main.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+void printArr(int* arr, int arrSize) {
+	printf("[");
+	for (int i = 0; i < arrSize; i++) {
+		printf(" %d ", arr[i]);
+	}
+	printf("]\n");
+}
+
+int removeElement(int* nums, int numsSize, int val) {
+    int endPointer = numsSize - 1;
+    int i = 0;
+    while (i < endPointer + 1) {
+        if (nums[i] == val) {
+            // Find a valid element to swap, if one is not found
+            // then return the current length
+            while (nums[endPointer] == val && endPointer > i) {
+                endPointer--;
+            }
+            if (endPointer == i) {
+                return i;
+            }
+            nums[i] = nums[endPointer--];
+        }
+	i++;
+    }
+    return i;
+}
+
+int main() {
+	int* arr = malloc(sizeof(int) * 8);
+	arr[0] = 0;
+	arr[1] = 1;
+	arr[2] = 2;
+	arr[3] = 2;
+	arr[4] = 3;
+	arr[5] = 0;
+	arr[6] = 4;
+	arr[7] = 2;
+	int result = removeElement(arr, 8, 2);
+	printf("Expected: [ 0 1 4 0 3 ]\nGot: ");
+	printArr(arr, result);
+	return 0;
+}

problems/27/problem.txt

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+Given an array nums and a value val, remove all instances of that value in-place and return the new length.
+
+Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.
+
+The order of elements can be changed. It doesn't matter what you leave beyond the new length.
+
+Example 1:
+
+Given nums = [3,2,2,3], val = 3,
+
+Your function should return length = 2, with the first two elements of nums being 2.
+
+It doesn't matter what you leave beyond the returned length.
+
+Example 2:
+
+Given nums = [0,1,2,2,3,0,4,2], val = 2,
+
+Your function should return length = 5, with the first five elements of nums containing 0, 1, 3, 0, and 4.
+
+Note that the order of those five elements can be arbitrary.
+
+It doesn't matter what values are set beyond the returned length.
+
+Clarification:
+
+Confused why the returned value is an integer but your answer is an array?
+
+Note that the input array is passed in by reference, which means modification to the input array will be known to the caller as well.
+
+Internally you can think of this:
+
+// nums is passed in by reference. (i.e., without making a copy)
+int len = removeElement(nums, val);
+
+// any modification to nums in your function would be known by the caller.
+// using the length returned by your function, it prints the first len elements.
+for (int i = 0; i < len; i++) {
+    print(nums[i]);
+}

problems/27/run.sh

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+#!/bin/bash
+
+gcc -o main main.c
+./main
+rm main