Refine 1304_Find_N_Unique_Integers_Sum_up_to_Zero

Author: qiyuangong

README.md

@@ -227,6 +227,7 @@ I'm currently working on [Analytics-Zoo](https://github.com/intel-analytics/anal
 | 1108 | [Defanging an IP Address](https://leetcode.com/problems/defanging-an-ip-address/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/1108_Defanging_an_IP_Address.py) [Java](https://github.com/qiyuangong/leetcode/blob/master/java/1108_Defanging_an_IP_Address.java) | String manipulate (split, replace and join), O(n) and O(n) |
 | 1260 | [Shift 2D Grid](https://leetcode.com/problems/shift-2d-grid/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/1260_Shift_2D_Grid.py) [Java](https://github.com/qiyuangong/leetcode/blob/master/java/1260_Shift_2D_Grid.java) | Final position of each element can be computed according to k, m and n, e.g., k == mn, then don't move, O(mn) and O(mn) |
 | 1290 | [Convert Binary Number in a Linked List to Integer](https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/1290_Convert_Binary_Number_in_a_Linked_List_to_Integer.py) | Take 2 to the power digit position from right (starting from 0) and multiply it with the digit |
+| 1304 | [Find N Unique Integers Sum up to Zero](https://leetcode.com/problems/find-n-unique-integers-sum-up-to-zero/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/1304_Find_N_Unique_Integers_Sum_up_to_Zero.py) [Java](https://github.com/qiyuangong/leetcode/blob/master/java/1304_Find_N_Unique_Integers_Sum_up_to_Zero.java) | [1,n-1] and its negative sum |
 | 1323 | [Maximum 69 Number](https://leetcode.com/problems/maximum-69-number/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/1323_Maximum_69_Number.py) [Java](https://github.com/qiyuangong/leetcode/blob/master/java/1323_Maximum_69_Number.java) | 9 is greater than 6, so change first 6 to 9 from left if exist, O(n) and O(1) |
 | 1337 | [The K Weakest Rows in a Matrix](https://leetcode.com/problems/the-k-weakest-rows-in-a-matrix/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/1337_The_K_Weakest_Rows_in_a_Matrix.py) [Java](https://github.com/qiyuangong/leetcode/blob/master/java/1337_The_K_Weakest_Rows_in_a_Matrix.java) | Check by row, from left to right, until encount first zero, O(mn) and O(1) |
 | 1342 | [Number of Steps to Reduce a Number to Zero](https://leetcode.com/problems/number-of-steps-to-reduce-a-number-to-zero/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/1342_Number_of_Steps_to_Reduce_a_Number_to_Zero.py) | If number is divisible by 2, divide the number by 2, else subtract 1 from the number, and output the number of steps, O(logn) and O(1) |

java/1304_Find_N_Unique_Integers_Sum_up_to_Zero.java

@@ -0,0 +1,9 @@
+public int[] sumZero(int n) {
+    int[] res = new int[n];
+    // place negative sum(from 1 to n-1) in 0
+    for (int i = 1; i < n; i++) {
+        res[i] = i;
+        res[0] -= i;
+    }
+    return res;
+}

python/1304_Find_N_Unique_Integers_Sum_up_to_Zero

@@ -0,0 +1,17 @@
+class Solution:
+    def sumZero(self, n: int) -> List[int]:
+        prefix_sum = 0
+        res = []
+        # 1, n-1
+        for i in range(1, n):
+            res.append(i)
+            prefix_sum = prefix_sum + i
+        # sum(from 1 to n-1)
+        res.append(-prefix_sum)
+        return res
+    
+    # def sumZero(self, n: int) -> List[int]:
+    #     # 1,n-1
+    #     prefix = list(range(1, n))
+    #     # sum(from 1 to n-1)
+    #     return prefix + [-sum(prefix)]