Javascript counting valleys
function countingValleys(n, s) {
const min = 2;
const max = 1000000;
let isInValley = false;
let valleys = 0;
s = (typeof s === "string") ? s.split('') : s;
if (s.length >= min
&& s.length <= max
&& n === parseInt(n, 0)
&& n >= min
&& n <= max
&& n === s.length) {
s.map(steps => ((steps === "U") ? 1 : -1))
.reduce((prev, next) => {
if (prev < 0 && !isInValley) {
isInValley = true;
}
if ((prev + next) === 0 && isInValley) {
valleys++;
isInValley = false;
}
return prev + next;
});
}
return valleys;
}