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Restore_IP_Addresses.cc
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Restore_IP_Addresses.cc
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class Solution {
public:
bool judge(string &s, int st) {
int num = 0;
for (int i = 0; i < 3; i++) {
num = num * 10 + (s[st + i] - '0');
}
if (num >= 0 && num <= 255) {
return true;
}
return false;
}
vector<string> restoreIpAddresses(string s) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
vector<string> ans;
int len = s.length(), slen;
if (len < 4 || len > 12) {
return ans;
}
for (int i = 1; i <= 3; i++) {
if (i >= 2 && s[0] == '0') {
break;
}
if (i == 3 && judge(s, 0) == false) {
break;
}
for (int j = 1; j <=3 && i + j < len; j++) {
if (j >= 2 && s[i] == '0') {
break;
}
if (j == 3 && judge(s, i) == false) {
break;
}
for (int k = 1; k <= 3 && i + j + k < len; k++) {
if (k >= 2 && s[i + j] == '0') {
break;
}
if (k == 3 && judge(s, i + j) == false) {
break;
}
slen = len - i - j - k;
if (slen > 3 || (slen == 3 && judge(s, i + j + k) == false)) {
continue;
}
if (slen >= 2 && s[i + j + k] == '0') {
continue;
}
string tmp = "";
tmp += s.substr(0, i);
tmp += '.';
tmp += s.substr(i, j);
tmp += '.';
tmp += s.substr(i + j, k);
tmp += '.';
tmp += s.substr(i + j + k, slen);
ans.push_back(tmp);
}
}
}
return ans;
}
};