Top 10 FAANG Coding Interview Questions Asked by Amazon and Google

#include <stdio.h>
#include <stdlib.h>

void findPair(int arr[], int size, int target) {
    for (int i = 0; i < size; i++) {
        for (int j = i + 1; j < size; j++) {
            if (arr[i] + arr[j] == target) {
                printf("%d %d\n", arr[i], arr[j]);
                return;
            }
        }
    }
    printf("No pair found\n");
}

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int target = 9;
    int size = sizeof(arr) / sizeof(arr[0]);
    findPair(arr, size, target);
    return 0;
}

#include <stdio.h>

void moveZeroes(int* nums, int size) {
    int count = 0; // Count of non-zero elements
    for (int i = 0; i < size; i++) {
        if (nums[i] != 0) {
            nums[count++] = nums[i];
        }
    }
    while (count < size) {
        nums[count++] = 0;
    }
}

int main() {
    int nums[] = {0, 1, 0, 3, 12};
    int size = sizeof(nums) / sizeof(nums[0]);
    moveZeroes(nums, size);
    for (int i = 0; i < size; i++) {
        printf("%d ", nums[i]);
    }
    return 0;
}

#include <stdio.h>
#include <limits.h>

int maxSubArraySum(int arr[], int n) {
    int max_so_far = INT_MIN, max_ending_here = 0;
    for (int i = 0; i < n; i++) {
        max_ending_here += arr[i];
        if (max_so_far < max_ending_here) {
            max_so_far = max_ending_here;
        }
        if (max_ending_here < 0) {
            max_ending_here = 0;
        }
    }
    return max_so_far;
}

int main() {
    int n;
    scanf("%d", &n);
    int arr[n];
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }
    printf("%d\n", maxSubArraySum(arr, n));
    return 0;
}

#include <stdio.h>

void rotate(int* nums, int numsSize, int k) {
    k = k % numsSize;
    if (k == 0) return;
    int temp[numsSize];
    for (int i = 0; i < numsSize; i++) {
        temp[(i + k) % numsSize] = nums[i];
    }
    for (int i = 0; i < numsSize; i++) {
        nums[i] = temp[i];
    }
}

int main() {
    int nums[] = {1, 2, 3, 4, 5, 6, 7};
    int k = 3;
    int numsSize = sizeof(nums) / sizeof(nums[0]);
    rotate(nums, numsSize, k);
    for (int i = 0; i < numsSize; i++) {
        printf("%d ", nums[i]);
    }
    return 0;
}

#include <stdio.h>

void merge(int arr1[], int n1, int arr2[], int n2, int merged[]) {
    int i = 0, j = 0, k = 0;
    while (i < n1 && j < n2) {
        if (arr1[i] < arr2[j]) {
            merged[k++] = arr1[i++];
        } else {
            merged[k++] = arr2[j++];
        }
    }
    while (i < n1) {
        merged[k++] = arr1[i++];
    }
    while (j < n2) {
        merged[k++] = arr2[j++];
    }
}

int main() {
    int arr1[] = {1, 3, 5};
    int arr2[] = {2, 4, 6};
    int n1 = sizeof(arr1) / sizeof(arr1[0]);
    int n2 = sizeof(arr2) / sizeof(arr2[0]);
    int merged[n1 + n2];
    merge(arr1, n1, arr2, n2, merged);
    for (int i = 0; i < n1 + n2; i++) {
        printf("%d ", merged[i]);
    }
    return 0;
}

#include <stdio.h>
#include <stdlib.h>

int majorityElement(int* nums, int numsSize) {
    int count = 0, candidate = 0;
    for (int i = 0; i < numsSize; i++) {
        if (count == 0) {
            candidate = nums[i];
        }
        count += (nums[i] == candidate) ? 1 : -1;
    }
    return candidate;
}

int main() {
    int nums[] = {2, 2, 1, 1, 1, 2, 2};
    int size = sizeof(nums) / sizeof(nums[0]);
    printf("%d\n", majorityElement(nums, size));
    return 0;
}

#include <stdio.h>

int findMissingNumber(int arr[], int n) {
    int total = (n * (n + 1)) / 2;
    int sum = 0;
    for (int i = 0; i < n - 1; i++) {
        sum += arr[i];
    }
    return total - sum;
}

int main() {
    int n;
    scanf("%d", &n);
    int arr[n - 1];
    for (int i = 0; i < n - 1; i++) {
        scanf("%d", &arr[i]);
    }
    printf("%d\n", findMissingNumber(arr, n));
    return 0;
}

#include <stdio.h>
#include <stdlib.h>

int findDuplicate(int* nums, int numsSize) {
    int slow = nums[0];
    int fast = nums[0];
    do {
        slow = nums[slow];
        fast = nums[nums[fast]];
    } while (slow != fast);

    slow = nums[0];
    while (slow != fast) {
        slow = nums[slow];
        fast = nums[fast];
    }
    return slow;
}

int main() {
    int nums[] = {1, 3, 4, 2, 2};
    int size = sizeof(nums) / sizeof(nums[0]);
    int duplicate = findDuplicate(nums, size);
    printf("%d\n", duplicate);
    return 0;
}

#include <stdio.h>

void productExceptSelf(int* nums, int numsSize, int* output) {
    int left[numsSize];
    int right[numsSize];
    left[0] = 1;
    right[numsSize - 1] = 1;

    for (int i = 1; i < numsSize; i++) {
        left[i] = left[i - 1] * nums[i - 1];
    }

    for (int i = numsSize - 2; i >= 0; i--) {
        right[i] = right[i + 1] * nums[i + 1];
    }

    for (int i = 0; i < numsSize; i++) {
        output[i] = left[i] * right[i];
    }
}

int main() {
    int nums[] = {1, 2, 3, 4};
    int numsSize = sizeof(nums) / sizeof(nums[0]);
    int output[numsSize];
    productExceptSelf(nums, numsSize, output);
    for (int i = 0; i < numsSize; i++) {
        printf("%d ", output[i]);
    }
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

int compare(const void *a, const void *b) {
    return (*(int*)a - *(int*)b);
}

int longestConsecutive(int* nums, int numsSize) {
    if (numsSize == 0) return 0;
    qsort(nums, numsSize, sizeof(int), compare);
    int longestStreak = 1, currentStreak = 1;
    for (int i = 1; i < numsSize; i++) {
        if (nums[i] == nums[i - 1]) continue;
        if (nums[i] == nums[i - 1] + 1) {
            currentStreak++;
        } else {
            longestStreak = currentStreak > longestStreak ? currentStreak : longestStreak;
            currentStreak = 1;
        }
    }
    return longestStreak > currentStreak ? longestStreak : currentStreak;
}

int main() {
    int nums[] = {100, 4, 200, 1, 3, 2};
    int size = sizeof(nums) / sizeof(nums[0]);
    printf("%d\n", longestConsecutive(nums, size));
    return 0;
}