Function findTargetSumWays

javascript/0494-target-sum.js:9–19

(nums, target, index = 0, sum = 0)

 * @return {number}
 */
var findTargetSumWays = (nums, target, index = 0, sum = 0) => {
    const isBaseCase = index === nums.length;
    if (isBaseCase) {
        const isTarget = sum === target;
        if (isTarget) return 1;

        return 0;
    }

    return dfs(nums, target, index, sum); /* Time O(2^N) | Space O(HEIGHT) */
};

var dfs = (nums, target, index, sum) => {
    const left = findTargetSumWays(