Two string - JavaScript, things I like: using j== first.length to determine YES/ NO, the big problem of coding - repeat same code in if/ else code.

Twostring6.js

function processData(input) {
    //Enter your code here
    var inputs = input.split('\n');
    var t = parseInt(inputs[0]);
    for(var i = 0; i < t; i++ ){
        var first = inputs[2*i+1];
        var second = inputs[2*i+2];
        if(first.length < second.length){
            for(var j = 0; j <first.length; j++){
                if(second.indexOf(first[j]) != -1)
                    break;
            }
            if(j==first.length)
                console.log("NO");
            else
                console.log("YES");
        }else{
            for(var j = 0; j <second.length; j++){
                if(first.indexOf(second[j]) != -1)
                    break;
            }
            if(j==second.length)
                console.log("NO");
            else
                console.log("YES");
        }
    }
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
   processData(_input);
});