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-rw-r--r--other/restore_ip_addr.cpp56
1 files changed, 56 insertions, 0 deletions
diff --git a/other/restore_ip_addr.cpp b/other/restore_ip_addr.cpp
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+++ b/other/restore_ip_addr.cpp
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+// 93. Restore IP Addresses
+#include "leetcode.h"
+
+/*
+ * a valid ip address consists of exactly 4 integers separated by single dots
+ * each integer is between 0 and 255 (inclusive) and cannot have leading 0's
+ * given: string 's' containing only digits, return all possible valid ip
+ * addresses that can be formed by insert dots into 's'. digits cannot be
+ * reordered or removed. return addresses in any order.
+ */
+
+class Solution {
+public:
+ vector<string> restoreIpAddresses(string s) {
+ vector<string> ans;
+ string ip;
+ dfs(s, 0, 0, ip, ans);
+ return ans;
+ }
+
+private:
+ void dfs(string s, int start, int step, string ip, vector<string> &res) {
+ if (start == s.size() && step == 4) {
+ ip.erase(ip.end() - 1);
+ res.push_back(ip);
+ return;
+ }
+ if (s.size() - start > (4 - step) * 3)
+ return;
+ if (s.size() - start < (4 - step))
+ return;
+ int num = 0;
+ for (int i = start; i < start + 3; i++) {
+ num = num * 10 + (s[i] - '0');
+ if (num <= 255) {
+ ip += s[i];
+ dfs(s, i + 1, step + 1, ip + '.', res);
+ }
+ if (num == 0)
+ break;
+ }
+ }
+};
+
+int main() {
+ Solution obj;
+ for (auto i : obj.restoreIpAddresses("25525511135"))
+ cout << i; // expect: 255.255.11.135","255.255.111.35
+ cout << endl;
+ for (auto i : obj.restoreIpAddresses("0000"))
+ cout << i; // expect: 0.0.0.0
+ cout << endl;
+ for (auto i : obj.restoreIpAddresses("101023"))
+ cout << i; // expect: 1.0.10.23,1.0.102.3,10.1.0.23,10.10.2.3,101.0.2.3
+ cout << endl;
+}