3 problems

Author: hitzzc

README.md

@@ -237,6 +237,9 @@ Golang solution for leetcode. For each problem, there is a simple *_test.go to t
 #### [327. Count of Range Sum](https://github.com/hitzzc/go-leetcode/tree/master/count_of_range_sum)
 #### [329. Longest Increasing Path in a Matrix](https://github.com/hitzzc/go-leetcode/tree/master/longest_increasing_path_in_a_matrix)
 #### [331. Verify Preorder Serialization of a Binary Tree](https://github.com/hitzzc/go-leetcode/tree/master/verify_preorder_serialization_of_a_binary_tree)
+#### [332. Reconstruct Itinerary](https://github.com/hitzzc/go-leetcode/tree/master/reconstruct_ltinerary)
+#### [334. Increasing Triplet Subsequence](https://github.com/hitzzc/go-leetcode/tree/master/increasing_triplet_subsequence)
+#### [335. Self Crossing](https://github.com/hitzzc/go-leetcode/tree/master/self_crossing)
 
 
 

increasing_triplet_subsequence/increasing_triplet_subsequence.cpp

@@ -0,0 +1,13 @@
+class Solution {
+public:
+    bool increasingTriplet(vector<int>& nums) {
+        if (nums.size() < 3) return false;
+        int first = nums[0], second = INT_MAX;
+        for (int i = 1; i < nums.size(); ++i) {
+        	if (nums[i] > second) return true;
+        	else if (nums[i] < first) first= nums[i];
+        	else if (nums[i] > first && nums[i] < second) second = nums[i];
+        }
+        return false;
+    }
+};

reconstruct_ltinerary/reconstruct_ltinerary.cpp

@@ -0,0 +1,21 @@
+class Solution {
+public:
+    vector<string> findItinerary(vector<pair<string, string>> tickets) {
+		unordered_map<string, multiset<string>> graph;
+		for (auto& kv: tickets) {
+			graph[kv.first].insert(kv.second);
+		}
+		vector<string> solution;
+		DFS(graph, solution, "JFK");
+		return vector<string>(solution.rbegin(), solution.rend());
+    }
+    void DFS(unordered_map<string, multiset<string>>& graph, vector<string>& solution, string start) {
+    	while (!graph[start].empty()) {
+    		string city = *graph[start].begin();
+    		graph[start].erase(city);
+    		(DFS(graph, solution, city));
+    	}
+    	solution.push_back(start);
+    	return;
+    }
+};

self_crossing/self_crossing.cpp

@@ -0,0 +1,15 @@
+class Solution {
+public:
+    bool isSelfCrossing(vector<int>& x) {
+       int m = x.size();
+       for(int i=0; i<m; ++i){
+           if(i>=3 && x[i]>=x[i-2] && x[i-3]>=x[i-1])
+                return true;    
+            if(i>=4 && x[i-1]==x[i-3] && x[i]+x[i-4]>=x[i-2])
+                return true;
+            if(i>=5 && x[i-3]>x[i-1] && x[i-2]>x[i-4] && x[i]+x[i-4]>=x[i-2] && x[i-1]+x[i-5]>=x[i-3])
+                return true;
+       }
+       return false;
+    }
+};