From 976a881e6958b38c7806937cff9d57800fb72d24 Mon Sep 17 00:00:00 2001 From: Ananya Ravikiran Vastare <116643029+Ananya-vastare@users.noreply.github.com> Date: Sun, 10 Nov 2024 09:22:38 +0530 Subject: [PATCH] Add files via upload --- .../Cycle detection using dfs/Readme.md | 49 +++++++++++++++++++ .../Cycle detection using dfs/code.c | 49 +++++++++++++++++++ 2 files changed, 98 insertions(+) create mode 100644 Graph Algorithms/Cycle detection using dfs/Readme.md create mode 100644 Graph Algorithms/Cycle detection using dfs/code.c diff --git a/Graph Algorithms/Cycle detection using dfs/Readme.md b/Graph Algorithms/Cycle detection using dfs/Readme.md new file mode 100644 index 00000000..82a97089 --- /dev/null +++ b/Graph Algorithms/Cycle detection using dfs/Readme.md @@ -0,0 +1,49 @@ +# Longest Increasing Subsequence in C + +This program calculates the **Longest Increasing Subsequence (LIS)** in an array of integers, using dynamic programming. It allows users to input the array size and its elements, then outputs the length of the longest increasing subsequence. + +## How It Works + +The program uses a dynamic programming approach where: +- An auxiliary array, `lis`, is maintained to store the LIS length at each index. +- For each element, it calculates the maximum LIS that ends at that position by considering all previous elements. +- Finally, it finds the maximum value in the `lis` array to determine the length of the longest increasing subsequence. + +### Time Complexity +The time complexity of this approach is **O(n²)** due to the nested loops. + +### Space Complexity +The space complexity is **O(n)**, as it uses an auxiliary array `lis` of the same length as the input array. + +## Getting Started + +### Prerequisites + +- A C compiler (like GCC). + +### Running the Program + +1. **Clone the Repository** (optional if using version control): + ```bash + git clone https://github.com/your-username/longest-increasing-subsequence + cd longest-increasing-subsequence +2. **Compile the Code **: + +```bash + Copy code + gcc lis.c -o lis + +3. **Run the Program**: + +```bash + Copy code + ./lis + +**Example Usage** +```bash +Enter the number of elements in the array: 9 +Enter the elements of the array: +10 22 9 33 21 50 41 60 80 +Length of LIS is 6 + +In this example, the longest increasing subsequence is [10, 22, 33, 50, 60, 80] with a length of 6. \ No newline at end of file diff --git a/Graph Algorithms/Cycle detection using dfs/code.c b/Graph Algorithms/Cycle detection using dfs/code.c new file mode 100644 index 00000000..1c9cd245 --- /dev/null +++ b/Graph Algorithms/Cycle detection using dfs/code.c @@ -0,0 +1,49 @@ +#include + +int longestIncreasingSubsequence(int arr[], int n) +{ + int lis[n]; + for (int i = 0; i < n; i++) + lis[i] = 1; // Initialize LIS values for all indexes as 1 + + for (int i = 1; i < n; i++) + { + for (int j = 0; j < i; j++) + { + if (arr[i] > arr[j] && lis[i] < lis[j] + 1) + { + lis[i] = lis[j] + 1; + } + } + } + + int max = 0; + for (int i = 0; i < n; i++) + { + if (max < lis[i]) + max = lis[i]; + } + return max; +} + +int main() +{ + int n; + + // Take the number of elements as input + printf("Enter the number of elements in the array: "); + scanf("%d", &n); + + int arr[n]; + + // Take array elements as input + printf("Enter the elements of the array:\n"); + for (int i = 0; i < n; i++) + { + scanf("%d", &arr[i]); + } + + // Calculate and print the length of LIS + printf("Length of LIS is %d\n", longestIncreasingSubsequence(arr, n)); + return 0; +}