DSA Day 1 👩‍💻

Topic: Array

Questions Attempted : 3

Questions Successfully Completed: 2

Missing number in array

Time Complexity : O(n)

Space Complexity : O(1)

int MissingNumber(int array[], int n) {

        int sum=0;
        int two_sum=0;
        for(int i=1;i<=n;i++){
            two_sum = two_sum + i;
        }
        for(int i=0;i<n-1;i++){
            sum = sum + array[i];
        }
        return two_sum-sum;
    }

Peak Element

Time Complexity : O(n)

Space Complexity : O(1)

public int peakElement(int[] arr,int n)
    {
        if(n==1){
            return 0;
        }
        if(arr[n-1]>=arr[n-2]){
            return n-1;
        }
        if(arr[0]>=arr[1]){
            return 0;
        }
        else{
            for(int i=1;i<n-1;i++){
    if((arr[i]>=arr[i+1]) && (arr[i]>=arr[i-1])){
                    return i;
                }
            }
        }
        return 0;
    }