Create 56-merge-intervals.js

Author: everthis

56-merge-intervals.js

@@ -0,0 +1,42 @@
+/**
+ * Definition for an interval.
+ * function Interval(start, end) {
+ *     this.start = start;
+ *     this.end = end;
+ * }
+ */
+/**
+ * @param {Interval[]} intervals
+ * @return {Interval[]}
+ */
+const merge = function(intervals) {
+    const hash = {}
+    intervals.forEach(el => {
+        if (hash.hasOwnProperty(el.start)) {
+            hash[el.start][1] = Math.max(hash[el.start][1], el.end)
+        } else {
+            hash[el.start] = [el.start, el.end]
+        }
+    })
+
+    const startArr = Object.keys(hash).sort((a, b) => +a - +b)
+    const res = []
+
+    while(startArr.length) {
+        let start = startArr.shift()
+        let end = hash[start][1]
+        
+        for(let i = 0; i < startArr.length; ) {
+            if (+startArr[i] <= end) {
+                end = Math.max(end, hash[startArr[i]][1])
+                startArr.shift()
+            } else {
+                break
+            }
+        }
+        let ins = new Interval(+start, end)
+        res.push(ins)
+
+    }
+    return res
+};