Restore IP Addresses

来源：互联网发布：淘宝分流怎么设置编辑：程序博客网时间：2024/06/05 20:45

枚举即可，但是小错误不断。

需要注意的是，有前导0的也属于不合法地址，不能被算进来。

class Solution {public:    vector<string> restoreIpAddresses(string s) {        vector<string> res;    int n = s.length();    int i, j, k;    vector<string> tmp;    for (i = 1; i < 4; ++i) {    for (j = 1; j < 4; ++j) {    for (k = 1; k < 4; ++k) {    int p = n - i - j - k;    if (p < 0 || p > 3)    continue;    tmp.clear();    tmp.push_back(s.substr(0, i));    tmp.push_back(s.substr(i, j));    tmp.push_back(s.substr(i + j, k));    tmp.push_back(s.substr(i + j + k, p));    if (isValid(tmp)) {    string t;    for (int m = 0; m < tmp.size() - 1; ++m)    t += tmp[m] + ".";    t += tmp[3];    res.push_back(t);    }    }    }    }    return res;    }        bool isValid(vector<string> split) {        for (int i = 0; i < split.size(); ++i) {            if (split[i] == "")                return false;            if (atoi(split[i].c_str()) > 255 || atoi(split[i].c_str()) < 0)                return false;            if (split[i].size() > 1 && split[i][0] == '0')                return false;        }        return true;    }};

http://oj.leetcode.com/problems/restore-ip-addresses/