CSE2012 PP1 Q3

/*
3.	Suppose an array A has n distinct integers. Write an algorithm to find an index k (k need not exist/ need not be unique) such that  A[0].........A[k] is an increasing sequence  and  A[k+1]........A[n-1] is a decreasing sequence.
Example:
A = {5,4, 3, 2, 1} Here k=0, A[0] is an increasing sequence and A[1,4] = {4,3,2,1} is decreasing.
A = {2, 4, 6, 5, 2, 1} then k can be 1 or 2.
A = {1, 3, 5, 4, 6, 2} k does not exists
*/

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

void solve(){
    unsigned int size;
    int *arr;

    //Input
    printf("\nEnter the size of array: ");
    scanf("%u", &size);
    arr = (int *)malloc(sizeof(int)*size);

    printf("\nInput values: ");
    int i;
    for(i = 0; i < size; i++){
        scanf("%d", &arr[i]);
    }

    //Solving

    int k = 0;

    while(k < size && arr[k+1] > arr[k]){
        k++;
    }

    /* //redundant
    if (k == size-1){
        printf("\nk=%d\n", k);
        return;
    }
    */

    for(i = k+1; i < size; i++){
        if (arr[i]>arr[i-1]){
            printf("\nk does not exist\n");
            return;
        }
    }

    printf("\nk=%d\n", k);
}

int main(){
    solve();
    return 0;
}