Why this code giving me NaN as an output???
var rob = function(nums) {
var a = 0;
var b = 0;
for (let i = 0; i < nums.length; i++) {
a += nums[i] + nums[i + 2]
b += nums[i + 1] + nums[i + 2]
}
return a
};
console.log(rob([1, 2, 3, 1]));You iterate through the array nums and then trying to access its members beyond its last element.
When i is 3, nums[i+2] refers to nonexisting element, yielding undefined, and when you add a number to undefined, you get NaN.
There are four items in the array [1, 2, 3, 1]. The issue is i+2.
In third iteration of the loop, you are trying to access an index that doesn't exist: nums[i + 2] in third iteration becomes nums[2 + 2], which becomes nums[4]. But nums[3] is the last item, because the array length is only 4
When i, the index of the array nums is out of bounds nums[i] is undefined. And when you add any undefined to any number or NaN the result is NaN.
You can use nums[i+2] || 0 and nums[i+1] || 0 to avoid dealing with undefined. If your aim is to sum all elements with an even index, 0,2 ..., and put the result in a, a better approach might be as below. For a larger array you run the danger of adding some elements to the result more than once.
However, if that's your goal then you can retain nums[+2] || 0 and nums[i+1] || 0.
const rob = function(nums) {
let a = 0;
let b = 0;
for (let i = 0; i < nums.length; i = i + 2) {
a += nums[i];
b += nums[i+1] || 0;
}
return a;
};
console.log(rob([1, 2, 3, 1]));