202410032305
tags: #two-pointers

const getNextValidCharIndex = (str, end) => {
	let backspaceCount = 0;
	while (end >= 0) {
		if (str[end] === '#') {
			backspaceCount += 1;
		}
		else if (backspaceCount > 0) {
			backspaceCount -= 1;
		}
		else if (str[end] !== '#') {
			break;
		}
		end -= 1;
	}
	return end;
}

var backspaceCompare = function(s, t) {
	let idxS = s.length - 1;
	let idxT = t.length - 1;
	while (idxS >= 0 || idxT >= 0) {
		idxS = getNextValidCharIndex(s, idxS);
		idxT = getNextValidCharIndex(t, idxT);
		if (idxS < 0 && idxT < 0) {
			return true;
		}
		if (idxS < 0 || idxT < 0) {
			return false;
		}
		if (s[idxS] != t[idxT]) {
			return false;
		}
		idxS -= 1;
		idxT -= 1;
	}
	return true;
};

Reference

https://leetcode.com/problems/backspace-string-compare/