feat: add solutions to lc problem: No.0377. Combination Sum IV

neilwang0913 · Jul 24, 2021 · e08d1c5 · e08d1c5
1 parent 47333f4
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diff --git a/README.md b/README.md
@@ -200,6 +200,7 @@
 - [编辑距离](./solution/0000-0099/0072.Edit%20Distance/README.md)
 - [零钱兑换](./solution/0300-0399/0322.Coin%20Change/README.md)
 - [零钱兑换 II](./solution/0500-0599/0518.Coin%20Change%202/README.md)
+- [组合总和 Ⅳ](./solution/0300-0399/0377.Combination%20Sum%20IV/README.md)
 - [礼物的最大价值](./lcof/面试题47.%20礼物的最大价值/README.md)
 - [俄罗斯套娃信封问题](./solution/0300-0399/0354.Russian%20Doll%20Envelopes/README.md)
 

diff --git a/README_EN.md b/README_EN.md
@@ -194,6 +194,7 @@ Complete solutions to [LeetCode](https://leetcode.com/problemset/all/), [LCOF](h
 - [Edit Distance](./solution/0000-0099/0072.Edit%20Distance/README_EN.md)
 - [Coin Change](./solution/0300-0399/0322.Coin%20Change/README_EN.md)
 - [Coin Change 2](./solution/0500-0599/0518.Coin%20Change%202/README_EN.md)
+- [Combination Sum IV](./solution/0300-0399/0377.Combination%20Sum%20IV/README_EN.md)
 - [Russian Doll Envelopes](./solution/0300-0399/0354.Russian%20Doll%20Envelopes/README_EN.md)
 
 ### Backtracking

diff --git a/solution/0300-0399/0377.Combination Sum IV/README.md b/solution/0300-0399/0377.Combination Sum IV/README.md
@@ -51,7 +51,6 @@
 
 <p><strong>进阶：</strong>如果给定的数组中含有负数会发生什么？问题会产生何种变化？如果允许负数出现，需要向题目中添加哪些限制条件？</p>
 
-
 ## 解法
 
 <!-- 这里可写通用的实现逻辑 -->
@@ -67,13 +66,13 @@
 ```python
 class Solution:
     def combinationSum4(self, nums: List[int], target: int) -> int:
-        dp = [0 for i in range(target + 1)]
+        dp = [0] * (target + 1)
         dp[0] = 1
         for i in range(1, target + 1):
             for num in nums:
-                if i - num >= 0:
+                if i >= num:
                     dp[i] += dp[i - num]
-        return dp[target]
+        return dp[-1]
 ```
 
 ### **Java**
@@ -85,15 +84,52 @@ class Solution {
     public int combinationSum4(int[] nums, int target) {
         int[] dp = new int[target + 1];
         dp[0] = 1;
-        for (int i = 1; i <= target; i++) {
+        for (int i = 1; i <= target; ++i) {
+            for (int num : nums) {
+                if (i >= num) {
+                    dp[i] += dp[i - num];
+                }
+            }
+        }
+        return dp[target];
+    }
+}
+```
+
+### **C++**
+
+```cpp
+class Solution {
+public:
+    int combinationSum4(vector<int>& nums, int target) {
+        vector<int> dp(target + 1);
+        dp[0] = 1;
+        for (int i = 1; i <= target; ++i) {
             for (int num : nums) {
-                if (i - num >= 0) {
+                if (i >= num && dp[i - num] < INT_MAX - dp[i]) {
                     dp[i] += dp[i - num];
                 }
             }
         }
         return dp[target];
     }
+};
+```
+
+### **Go**
+
+```go
+func combinationSum4(nums []int, target int) int {
+	dp := make([]int, target+1)
+	dp[0] = 1
+	for i := 1; i <= target; i++ {
+		for _, num := range nums {
+			if i >= num {
+				dp[i] += dp[i-num]
+			}
+		}
+	}
+	return dp[target]
 }
 ```
 

diff --git a/solution/0300-0399/0377.Combination Sum IV/README_EN.md b/solution/0300-0399/0377.Combination Sum IV/README_EN.md
@@ -46,9 +46,10 @@ Note that different sequences are counted as different combinations.
 <p>&nbsp;</p>
 <p><strong>Follow up:</strong> What if negative numbers are allowed in the given array? How does it change the problem? What limitation we need to add to the question to allow negative numbers?</p>
 
-
 ## Solutions
 
+Dynamic programming.
+
 `dp[i]` represents the number of element combinations whose sum is `i`.
 
 <!-- tabs:start -->
@@ -58,13 +59,13 @@ Note that different sequences are counted as different combinations.
 ```python
 class Solution:
     def combinationSum4(self, nums: List[int], target: int) -> int:
-        dp = [0 for i in range(target + 1)]
+        dp = [0] * (target + 1)
         dp[0] = 1
         for i in range(1, target + 1):
             for num in nums:
-                if i - num >= 0:
+                if i >= num:
                     dp[i] += dp[i - num]
-        return dp[target]
+        return dp[-1]
 ```
 
 ### **Java**
@@ -74,9 +75,9 @@ class Solution {
     public int combinationSum4(int[] nums, int target) {
         int[] dp = new int[target + 1];
         dp[0] = 1;
-        for (int i = 1; i <= target; i++) {
+        for (int i = 1; i <= target; ++i) {
             for (int num : nums) {
-                if (i - num >= 0) {
+                if (i >= num) {
                     dp[i] += dp[i - num];
                 }
             }
@@ -86,6 +87,43 @@ class Solution {
 }
 ```
 
+### **C++**
+
+```cpp
+class Solution {
+public:
+    int combinationSum4(vector<int>& nums, int target) {
+        vector<int> dp(target + 1);
+        dp[0] = 1;
+        for (int i = 1; i <= target; ++i) {
+            for (int num : nums) {
+                if (i >= num && dp[i - num] < INT_MAX - dp[i]) {
+                    dp[i] += dp[i - num];
+                }
+            }
+        }
+        return dp[target];
+    }
+};
+```
+
+### **Go**
+
+```go
+func combinationSum4(nums []int, target int) int {
+	dp := make([]int, target+1)
+	dp[0] = 1
+	for i := 1; i <= target; i++ {
+		for _, num := range nums {
+			if i >= num {
+				dp[i] += dp[i-num]
+			}
+		}
+	}
+	return dp[target]
+}
+```
+
 ### **...**
 
 ```

diff --git a/solution/0300-0399/0377.Combination Sum IV/Solution.cpp b/solution/0300-0399/0377.Combination Sum IV/Solution.cpp
@@ -0,0 +1,15 @@
+class Solution {
+public:
+    int combinationSum4(vector<int>& nums, int target) {
+        vector<int> dp(target + 1);
+        dp[0] = 1;
+        for (int i = 1; i <= target; ++i) {
+            for (int num : nums) {
+                if (i >= num && dp[i - num] < INT_MAX - dp[i]) {
+                    dp[i] += dp[i - num];
+                }
+            }
+        }
+        return dp[target];
+    }
+};
diff --git a/solution/0300-0399/0377.Combination Sum IV/Solution.go b/solution/0300-0399/0377.Combination Sum IV/Solution.go
@@ -0,0 +1,12 @@
+func combinationSum4(nums []int, target int) int {
+	dp := make([]int, target+1)
+	dp[0] = 1
+	for i := 1; i <= target; i++ {
+		for _, num := range nums {
+			if i >= num {
+				dp[i] += dp[i-num]
+			}
+		}
+	}
+	return dp[target]
+}
diff --git a/solution/0300-0399/0377.Combination Sum IV/Solution.java b/solution/0300-0399/0377.Combination Sum IV/Solution.java
@@ -2,13 +2,13 @@ class Solution {
     public int combinationSum4(int[] nums, int target) {
         int[] dp = new int[target + 1];
         dp[0] = 1;
-        for (int i = 1; i <= target; i++) {
+        for (int i = 1; i <= target; ++i) {
             for (int num : nums) {
-                if (i - num >= 0) {
+                if (i >= num) {
                     dp[i] += dp[i - num];
                 }
             }
         }
         return dp[target];
     }
-}
+}
diff --git a/solution/0300-0399/0377.Combination Sum IV/Solution.py b/solution/0300-0399/0377.Combination Sum IV/Solution.py
@@ -1,9 +1,9 @@
 class Solution:
     def combinationSum4(self, nums: List[int], target: int) -> int:
-        dp = [0 for i in range(target + 1)]
+        dp = [0] * (target + 1)
         dp[0] = 1
         for i in range(1, target + 1):
             for num in nums:
-                if i - num >= 0:
+                if i >= num:
                     dp[i] += dp[i - num]
-        return dp[target]
+        return dp[-1]