From 8901afccf4214b867f0a8303360388683da8bd5e Mon Sep 17 00:00:00 2001
From: Sainnhe Park <i@sainnhe.dev>
Date: Wed, 16 Nov 2022 10:58:20 +0800
Subject: [PATCH] s0030

---
 ...string_with_concatenation_of_all_words.hpp | 15 +++++++++
 ...string_with_concatenation_of_all_words.cpp | 33 +++++++++++++++++++
 ...string_with_concatenation_of_all_words.cpp | 19 +++++++++++
 3 files changed, 67 insertions(+)
 create mode 100644 include/s0030_substring_with_concatenation_of_all_words.hpp
 create mode 100644 src/s0030_substring_with_concatenation_of_all_words.cpp
 create mode 100644 tests/s0030_substring_with_concatenation_of_all_words.cpp

diff --git a/include/s0030_substring_with_concatenation_of_all_words.hpp b/include/s0030_substring_with_concatenation_of_all_words.hpp
new file mode 100644
index 0000000..1e1cacc
--- /dev/null
+++ b/include/s0030_substring_with_concatenation_of_all_words.hpp
@@ -0,0 +1,15 @@
+#ifndef S0030_SUBSTRING_WITH_CONCATENATION_OF_ALL_WORDS
+#define S0030_SUBSTRING_WITH_CONCATENATION_OF_ALL_WORDS
+
+#include <vector>
+#include <string>
+#include <unordered_map>
+
+using namespace std;
+
+class Solution {
+ public:
+  vector<int> findSubstring(string s, vector<string>& words);
+};
+
+#endif
diff --git a/src/s0030_substring_with_concatenation_of_all_words.cpp b/src/s0030_substring_with_concatenation_of_all_words.cpp
new file mode 100644
index 0000000..5fc3584
--- /dev/null
+++ b/src/s0030_substring_with_concatenation_of_all_words.cpp
@@ -0,0 +1,33 @@
+#include "s0030_substring_with_concatenation_of_all_words.hpp"
+
+vector<int> Solution::findSubstring(string s, vector<string>& words) {
+  vector<int> res;
+  int m = words.size(), n = words[0].size(), ls = s.size();
+  for (int i = 0; i < n && i + m * n <= ls; ++i) {
+    unordered_map<string, int> differ;
+    for (int j = 0; j < m; ++j) {
+      ++differ[s.substr(i + j * n, n)];
+    }
+    for (string& word : words) {
+      if (--differ[word] == 0) {
+        differ.erase(word);
+      }
+    }
+    for (int start = i; start < ls - m * n + 1; start += n) {
+      if (start != i) {
+        string word = s.substr(start + (m - 1) * n, n);
+        if (++differ[word] == 0) {
+          differ.erase(word);
+        }
+        word = s.substr(start - n, n);
+        if (--differ[word] == 0) {
+          differ.erase(word);
+        }
+      }
+      if (differ.empty()) {
+        res.emplace_back(start);
+      }
+    }
+  }
+  return res;
+}
diff --git a/tests/s0030_substring_with_concatenation_of_all_words.cpp b/tests/s0030_substring_with_concatenation_of_all_words.cpp
new file mode 100644
index 0000000..93bad95
--- /dev/null
+++ b/tests/s0030_substring_with_concatenation_of_all_words.cpp
@@ -0,0 +1,19 @@
+#include "s0030_substring_with_concatenation_of_all_words.hpp"
+
+#include <gtest/gtest.h>
+
+TEST(Problem30, Case1) {
+  string s{"barfoothefoobarman"};
+  vector<string> words{"foo", "bar"};
+  vector<int> o{0, 9};
+  Solution solution;
+  EXPECT_EQ(solution.findSubstring(s, words), o);
+}
+
+TEST(Problem30, Case2) {
+  string s{"wordgoodgoodgoodbestword"};
+  vector<string> words{"word","good","best","word"};
+  vector<int> o{};
+  Solution solution;
+  EXPECT_EQ(solution.findSubstring(s, words), o);
+}