fix an add

rust-leetcode/README.md

 Leetcode Rust 实现
 --
 
-超简单的算法题目，主要为了熟悉rust语法。源码在Solution.rs，并包含测试
+超简单的算法题目，主要为了熟悉rust语法。源码在Solution.rs，并包含部分测试（均AC，90%是双100）
 
 不区分具体的LeetCode系列
 
@@ -538,3 +538,39 @@ impl Solution {
     }
 }
 ```
+* 和为零的N个唯一整数
+```rust
+impl Solution {
+    //双指针 平均分布，不同解决得到的结果不同
+    pub fn sum_zero(n: i32) -> Vec<i32> {
+        let mut ret = vec![0; n as usize];
+        let mut i = 0usize;
+        let mut j = (n - 1) as usize;
+        let mut c = 1;
+        loop {
+            if i >= j {
+                break;
+            }
+            ret[i] = c;
+            ret[j] = -c;
+            i += 1;
+            j -= 1;
+            c += 1;
+        }
+        ret
+    }
+    //[sum=1~n-2,-sum]
+    pub fn sum_zero2(n: i32) -> Vec<i32> {
+        let mut ret = vec![0; n as usize];
+        let mut sum = 0;
+        let mut j = 0;
+        for i in 0..=n - 2 {
+            ret[j] = i;
+            j += 1;
+            sum += i;
+        }
+        ret[(n - 1) as usize] = -sum;
+        ret
+    }
+}
+```

rust-leetcode/src/Solution.rs

@@ -764,6 +764,48 @@ fn leetcode_709() {
     println!("{}", ret)
 }
 
+///和为零的N个唯一整数
+fn leetcode_1304() {
+    println!("leetcode_1304");
+    impl Solution {
+        //双指针
+        pub fn sum_zero(n: i32) -> Vec<i32> {
+            let mut ret = vec![0; n as usize];
+            let mut i = 0usize;
+            let mut j = (n - 1) as usize;
+            let mut c = 1;
+            loop {
+                if i >= j {
+                    break;
+                }
+                ret[i] = c;
+                ret[j] = -c;
+                i += 1;
+                j -= 1;
+                c += 1;
+            }
+            ret
+        }
+
+        pub fn sum_zero2(n: i32) -> Vec<i32> {
+            let mut ret = vec![0; n as usize];
+            let mut sum = 0;
+            let mut j = 0;
+            for i in 0..=n - 2 {
+                ret[j] = i;
+                j += 1;
+                sum += i;
+            }
+            ret[(n - 1) as usize] = -sum;
+            ret
+        }
+    }
+    let ret = Solution::sum_zero(10);
+    let ret2 = Solution::sum_zero2(5);
+    print_vec(ret);
+    print_vec(ret2);
+}
+
 ///所有方法调用
 pub fn solutions() {
     interview_58_2();
@@ -789,6 +831,7 @@ pub fn solutions() {
     leetcode_617();
     leetcode_461();
     leetcode_709();
+    leetcode_1304();
 }
 
 fn print_vec(nums: Vec<i32>) {