题解 | #数字字符串转化成IP地址#

/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 *
 * @param s string字符串
 * @return string字符串一维数组
 */

function restoreCore(s, depth) {
    // 返回值是在该s的情况下，所有可能的返回值的数组
    if (s.length == 0) return [];
    if (depth == 3) {
        if (s[0] == "0" && s.length > 1) return [];
        let res = Number(s);
        return res > 255 ? [] : [s];
    }
    let cur = "";
    let res = [];
    let search = 3;
    if (s[0] == "0") {
        search = s.indexOf("0") == -1 ? search : s.indexOf("0") + 1;
    }
    for (let i = 1; i < search + 1; i++) {
        cur = cur + s[i - 1];
        if (Number(cur) > 255) {
            break;
        }
        let rest = restoreCore(s.slice(i), depth + 1);
        if (rest.length == 0) continue;
        for (let r of rest) {
            res.push(cur + "." + r);
        }
    }
    return res;
}

function restoreIpAddresses(s) {
    // write code here
    let res = restoreCore(s, 0);
    return res;
}
module.exports = {
    restoreIpAddresses: restoreIpAddresses,
};