How can we find second maximum from array efficiently?

Question

Is it possible to find the second maximum number from an array of integers by traversing the array only once?

As an example, I have a array of five integers from whi

Answer 1

Here is something which may work ,

public static int secondLargest(int[] a){
    int max=0;
    int secondMax=0;

    for(int i=0;i<a.length;i++){
        if(a[i]<max){
            if(a[i]>secondMax){
                secondMax=a[i];
            }
            continue;
        }

        if(a[i]>max){
            secondMax=max;
            max=a[i];
        }

    }
    return secondMax;
}

Answer 2

int max,secondMax;
max=secondMax=array[0];
                                                for(int i=0;i<array.length;i++)
    {                                                   if(array[i]>max)                                                    {                                           max=array[i];                                                   }
                                                        if(array[i]>secondMax && array[i]<max)                                                  {
    secondMax=array[i];                                                 }
    }

Answer 3

#include <iostream>
using namespace std;

int main() {

   int  max = 0;
    int sec_Max = 0;

    int array[] = {81,70,6,78,54,77,7,78};

    int loopcount = sizeof(array)/sizeof(int);

    for(int i = 0 ; i < loopcount ; ++i)
    {

        if(array[i]>max)
        {
            sec_Max = max;
            max = array[i];
        }

        if(array[i] > sec_Max && array[i] < max)
        {
            sec_Max = array[i];
        }
    }

    cout<<"Max:" << max << " Second Max: "<<sec_Max<<endl;

    return 0;
}

Answer 4

The easiest solution would be to use std::nth_element.