Update minimum-initial-energy-to-finish-tasks.cpp

Author: kamyu104

C++/minimum-initial-energy-to-finish-tasks.cpp

@@ -9,6 +9,7 @@ class Solution {
                  return a[1] - a[0] < b[1] - b[0];  // sort by waste in asc
              });
         int result = 0;
+        // you can see proof here, https://leetcode.com/problems/minimum-initial-energy-to-finish-tasks/discuss/944633/Explanation-on-why-sort-by-difference
         for (const auto& task : tasks) {  // we need to pick all the wastes, so greedily to pick the least waste first is always better
             result = max(result + task[0], task[1]);
         }