Solve #228

Author: aylei

src/lib.rs

@@ -195,3 +195,4 @@ mod n0224_basic_calculator;
 mod n0225_implement_stack_using_queues;
 mod n0226_invert_binary_tree;
 mod n0227_basic_calculator_ii;
+mod n0228_summary_ranges;

src/n0228_summary_ranges.rs

@@ -0,0 +1,66 @@
+/**
+ * [228] Summary Ranges
+ *
+ * Given a sorted integer array without duplicates, return the summary of its ranges.
+ *
+ * Example 1:
+ *
+ *
+ * Input:  [0,1,2,4,5,7]
+ * Output: ["0->2","4->5","7"]
+ * Explanation: 0,1,2 form a continuous range; 4,5 form a continuous range.
+ *
+ *
+ * Example 2:
+ *
+ *
+ * Input:  [0,2,3,4,6,8,9]
+ * Output: ["0","2->4","6","8->9"]
+ * Explanation: 2,3,4 form a continuous range; 8,9 form a continuous range.
+ *
+ *
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+impl Solution {
+    pub fn summary_ranges(nums: Vec<i32>) -> Vec<String> {
+        if nums.is_empty() { return vec![] }
+        let mut res = Vec::new();
+        let mut curr = nums[0];
+        let mut start = nums[0];
+        for num in nums.into_iter().skip(1) {
+            if num == curr + 1 {
+                curr = num;
+            } else {
+                // seq done
+                Solution::record(&mut res, start, curr);
+                start = num;
+                curr = num;
+            }
+        }
+        Solution::record(&mut res, start, curr);
+        res
+    }
+
+    pub fn record(vec: &mut Vec<String>, start: i32, end: i32) {
+        if start == end {
+            vec.push(format!("{}", start))
+        } else {
+            vec.push(format!("{}->{}", start, end))
+        }
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_228() {
+        assert_eq!(Solution::summary_ranges(vec![0,1,2,3,4,5,6]), vec_string!["0->6"]);
+    }
+}