c# console program

Question

1-wap in c# to find distinct no in an array and if not then return -1

i.e{1,2,2,3,4,3,1}.The output will be 4.if there is no distinct element it returns -1.The program should be dynamic.

 

2-Rearrange the string ,if the string is    "STUDENT" the o/p will be "STTNUED".This program should be dynamic.