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56 lines
1.4 KiB
56 lines
1.4 KiB
/*
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验证ipv4是否合法
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*/
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#include <bits/stdc++.h>
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using namespace std;
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vector<string> split(string s, string spliter) {
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vector<string> res;
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int i;
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//遍历字符串查找spliter
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while ((i = s.find(spliter)) && i != s.npos) {
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//将分割的部分加入vector中
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res.push_back(s.substr(0, i));
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s = s.substr(i + 1);
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}
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res.push_back(s);
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return res;
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}
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bool isIPv4(string IP) {
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vector<string> s = split(IP, ".");
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if (s.size() != 4)
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return false;
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for (int i = 0; i < s.size(); i++) {
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//不可缺省，有一个分割为零，说明两个点相连
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if (s[i].size() == 0)
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return false;
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//比较数字位数及不为零时不能有前缀零
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if (s[i].size() < 0 || s[i].size() > 3 || (s[i][0] == '0' && s[i].size() != 1))
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return false;
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//遍历每个分割字符串，必须为数字
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for (int j = 0; j < s[i].size(); j++)
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if (!isdigit(s[i][j]))
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return false;
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//转化为数字比较，0-255之间
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int num = stoi(s[i]);
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if (num < 0 || num > 255)
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return false;
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}
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return true;
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}
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int solve(string IP) {
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// write code here
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if (IP.size() == 0)
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return 0;
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if (isIPv4(IP))
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return 1;
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return 0;
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}
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int main() {
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string str;
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cin >> str;
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cout << solve(str) << endl;
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return 0;
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}
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