Jump Game II

Author: cshanbo

1.cpp

@@ -4,7 +4,7 @@
 Description: 
 Shanbo Cheng: [email protected] 
 Date: 2016-07-06 15:00:26
-Last modified: 2016-07-06 16:43:26
+Last modified: 2016-08-02 08:57:05
 GCC version: 4.7.3
 */
 

10.cpp

@@ -4,7 +4,7 @@
 Description: 
 Shanbo Cheng: [email protected]
 Date: 2016-07-19 20:12:52
-Last modified: 2016-07-19 20:27:38
+Last modified: 2016-08-02 10:44:08
 GCC version: 4.9.3
 ***********************************************************/
 

383.cpp

@@ -0,0 +1,29 @@
+//coding:utf-8
+/*****************************************
+Program: 383 ransom note
+Description: 
+Author: [email protected]
+Date: 2016-08-11 12:13:40
+Last modified: 2016-08-11 12:23:04
+GCC version: 4.9.3
+*****************************************/
+
+#include <unordered_map>
+class Solution {
+    unordered_map<char, int> count;
+public:
+    bool canConstruct(string ransomNote, string magazine) {
+        if(ransomNote.empty())
+            return true;
+        if(magazine.empty())
+            return false;
+        for(auto c: magazine)
+            count[c]++;
+        for(auto c: ransomNote) {
+            if(count.find(c) == count.end() || count[c] == 0)
+                return false;
+            count[c]--;
+        }
+        return true;
+    }
+};

39.cpp

@@ -4,7 +4,7 @@ Program: Combination Sum
 Description: 
 Shanbo Cheng: [email protected]
 Date: 2016-07-29 15:33:14
-Last modified: 2016-07-29 15:55:15
+Last modified: 2016-08-11 12:27:13
 GCC version: 4.9.3
 ***********************************************************/
 
@@ -14,6 +14,7 @@ GCC version: 4.9.3
 
 using namespace std;
 
+//standard backtracking solution
 class Solution {
     void helper(vector<int>& candidates, vector<vector<int>>& ret, vector<int>& one, int num, int index) {
         if(num == 0 || index == candidates.size()) {

45.cpp

@@ -0,0 +1,38 @@
+//coding:utf-8
+/*****************************************
+Program: Jump Game II
+Description: 
+Author: [email protected]
+Date: 2016-08-17 15:58:04
+Last modified: 2016-08-17 16:15:04
+GCC version: 4.9.3
+*****************************************/
+
+#include <vector>
+#include <iostream>
+using namespace std;
+
+class Solution {
+public:
+    int jump(vector<int>& nums) {
+        if(nums.size() <= 1)
+            return 0;
+        int i = 0, temp = 0, level = 0, maxJump = 0;
+        while(maxJump < nums.size()) {
+            level++;
+            for(; i <= temp; ++i) {
+                maxJump = max(maxJump, nums[i] + i);
+                if(maxJump >= nums.size() - 1)
+                    return level;
+            }
+            temp = maxJump;
+        }
+        return level - 1;
+    }
+};
+
+int main() {
+    vector<int> vec{2, 3, 1, 1, 3, 1};
+    Solution s;
+    cout << s.jump(vec) << endl;
+}