Merge pull request #764 from i-priyanshu/master

Added Merge_intervals fixes #763

Author: Saviour1001

Data Structures/Stacks/merge_intervals.cpp

@@ -0,0 +1,60 @@
+// Given a set of time intervals in any order, merge all overlapping intervals
+// into one and output the result which should have only mutually exclusive
+// intervals. Let the intervals be represented as pairs of integers for
+// simplicity. For example, let the given set of intervals be {{1,3}, {2,4},
+// {5,7}, {6,8}}. The intervals {1,3} and {2,4} overlap with each other, so they
+// should be merged and become {1, 4}. Similarly, {5, 7} and {6, 8} should be
+// merged and become {5, 8}.
+
+// Write a function that produces the set of merged intervals for the given set
+// of intervals.
+
+#include <bits/stdc++.h>
+using namespace std;
+struct Interval
+{
+    int start, end;
+};
+
+bool compare(Interval i1, Interval i2) { return (i1.start < i2.start); }
+
+void mergeIntervals(Interval arr[], int n)
+{
+    if (n <= 0)
+        return;
+    stack<Interval> s;
+    sort(arr, arr + n, compare);
+    s.push(arr[0]);
+
+    for (int i = 1; i < n; i++)
+    {
+        Interval top = s.top();
+
+        if (top.end < arr[i].start)
+            s.push(arr[i]);
+
+        else if (top.end < arr[i].end)
+        {
+            top.end = arr[i].end;
+            s.pop();
+            s.push(top);
+        }
+    }
+
+    cout << "\n The Merged Intervals are: ";
+    while (!s.empty())
+    {
+        Interval t = s.top();
+        cout << "[" << t.start << "," << t.end << "] ";
+        s.pop();
+    }
+    return;
+}
+
+int main()
+{
+    Interval arr[] = {{1, 3}, {2, 4}, {5, 7}, {6, 8}};
+    int n = sizeof(arr) / sizeof(arr[0]);
+    mergeIntervals(arr, n);
+    return 0;
+}