prime consecutive numbers, Javascript

prime consecutive numbers

/**
 * Created by ankit suman on 22-06-2017.
 *
 * Some prime numbers can be expressed as Sum of other consecutive prime numbers.
 For example
 5 = 2 + 3
 17 = 2 + 3 + 5 + 7
 41 = 2 + 3 + 5 + 7 + 11 + 13
 Your task is to find out how many prime numbers which satisfy this property are present in the range 3 to N subject to a constraint that summation should always start with number 2.
 Write code to find out number of prime numbers that satisfy the above mentioned property in a given range.
 Input Format:
 First line contains a number N
 Output Format:
 Print the total number of all such prime numbers which are less than or equal to N.
 Constraints:
 1. 2<N<=12,000,000,000

*/
/**
 * the number of prime values under 20 : 2,3,5,7,11,13,17,19
 */

/**
 *  steps: finding prime numbers
 *  and then finding summation starting from 2.
 *
 */

var stdin = process.openStdin();
console.log("enter the value of N :");
stdin.addListener("data", function (v) {

var n = parseInt(v);
    var arr = [],count=0;

if(n>12000000000 || n<3){
        console.log("range:<=12,000,000,000");
    }

for (var i = 2; i < n; i++) {
        // console.log(i);
        if (prime(i)) {
           //console.log(i);
            arr.push(i);
        }
    }

//console.log( arr);

for(var j=0;j<arr.length;j++){
            if(sum(arr,arr[j]))
                count++;
        }

console.log((count-1));
});

/**
 * prime
 * @return 1 for prime
 */

var prime = function (number) {

var flag = 1;
    for (var i = 2; i < number; i++) {
        if (number % i == 0) {
            flag = 0;
            break;
        }

}
    return flag;

};

var sum = function (ar, num) {
    var pri = [];var s=0,flag=0;
    for(var i=0;i<ar.length;++i){
       // console.log(s);
        s+=ar[i];
        pri.push(ar[i]);
        if(s==num) {
            flag=1;
            break;
        }
       // s+=ar[i];

}
//console.log(pri);
return flag;
};


run \| edit \| history \| help	0