CODECHEF CONTEST WRITEUP (RANGEASSIGN DIV 4)

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 Logic => 

    We can have atmost 2 distinct numbers

  1. if we have 1 distinct number then whole array is same or arr[0] == arr[n-1]
    1. [1,1,1,1] = [1,1,1,1] = [1]
    2. [1,2,3,1] = [1,1,1,1] = [1]
  2. If we have 2 distinct number then whole array then array will be divided into two parts => 
    1. [1,2,3,1,5,6,8,5] = [1,1,1,1,5,5,5,5] = [1,5]
    Conditions =>

  • if a[0] == a[n-1] then yes
  • else 
    • for(int i = 1 ; i < n ; i++){
    • if(arr[0] == arr[i] & arr[i+1] == arr[n-1] then YES
  • then NO

CODE = 

#include <stdio.h>
#include <stdlib.h>
int main(void) {
   
    int t;
    scanf("%d",&t);
   
    while(t--){
       
        int n;
        scanf("%d",&n);
       
        int arr[n];
        for(int i = 0 ; i < n ; i++){
            scanf("%d",&arr[i]);
        }
       
        int flag = 0;
        if(arr[0] == arr[n-1]){
            flag = 1;
        }else{
            for(int i = 0 ; i < n-1 ; i++){
                if(arr[i] == arr[0] && arr[i+1] == arr[n-1]){
                    flag = 1;
                }
            }
        }
       
        if(flag){
            printf("YES\n");
        }else{
            printf("NO\n");
        }
       
    }
    return 0;
}

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