@@ -55,11 +55,11 @@
 | [Graph](https://.com/fluency03/leetcode-java/blob/master/src/graph) |
 
 
-# Total: 533
+# Total: 534
 
 | Easy | Medium | Hard | - |
 |:-------:|:-------:|:----:|:---:|
-| 142 | 289 | 90 | 12 |
+| 142 | 290 | 90 | 12 |
 
 
 | Question | Solution | Difficulty |
@@ -474,6 +474,7 @@
 | [632. Smallest Range](https://leetcode.com/problems/smallest-range/) | [Solution](https://.com/fluency03/leetcode-java/blob/master/src/SmallestRange632.java) | Hard |
 | [633. Sum of Square Numbers](https://leetcode.com/problems/sum-of-square-numbers/) | [Solution](https://.com/fluency03/leetcode-java/blob/master/src/SumOfSquareNumbers633.java) | Easy |
 | [635. Design Log Storage System](https://leetcode.com/problems/design-log-storage-system/) | [Solution](https://.com/fluency03/leetcode-java/blob/master/src/DesignLogStorageSystem635.java) | Hard |
+| [636. Exclusive Time of Functions](https://leetcode.com/problems/exclusive-time-of-functions/) | [Solution](https://.com/fluency03/leetcode-java/blob/master/src/ExclusiveTimeOfFunctions636.java) | Medium |
 | [637. Average of Levels in Binary Tree](https://leetcode.com/problems/average-of-levels-in-binary-tree/) | [Solution](https://.com/fluency03/leetcode-java/blob/master/src/AverageOfLevelsInBinaryTree637.java) | Easy |
 | [639. Decode Ways II](https://leetcode.com/problems/decode-ways-ii/) | [Solution](https://.com/fluency03/leetcode-java/blob/master/src/DecodeWaysII639.java) | Hard |
 | [640. Solve the Equation](https://leetcode.com/problems/solve-the-equation/) | [Solution](https://.com/fluency03/leetcode-java/blob/master/src/SolveTheEquation640.java) | Medium |

@@ -0,0 +1,72 @@
+/**
+* Given the running logs of n functions that are executed in a nonpreemptive
+* single threaded CPU, find the exclusive time of these functions.
+*
+* Each function has a unique id, start from 0 to n-1. A function may be called
+* recursively or by another function.
+*
+* A log is a string has this format : function_id:start_or_end:timestamp. For
+* example, "0:start:0" means function 0 starts from the very beginning of
+* time 0. "0:end:0" means function 0 ends to the very end of time 0.
+*
+* Exclusive time of a function is defined as the time spent within this
+* function, the time spent by calling other functions should not be considered
+* as this function's exclusive time. You should return the exclusive time of
+* each function sorted by their function id.
+*
+* Example 1:
+* Input:
+* n = 2
+* logs =
+* ["0:start:0",
+* "1:start:2",
+* "1:end:5",
+* "0:end:6"]
+* Output:[3, 4]
+*
+* Explanation:
+* Function 0 starts at time 0, then it executes 2 units of time and reaches
+* the end of time 1.
+* Now function 0 calls function 1, function 1 starts at time 2, executes 4
+* units of time and end at time 5.
+* Function 0 is running again at time 6, and also end at the time 6, thus
+* executes 1 unit of time.
+* So function 0 totally execute 2 + 1 = 3 units of time, and function 1
+* totally execute 4 units of time.
+*
+* Note:
+* Input logs will be sorted by timestamp, NOT log id.
+* Your output should be sorted by function id, which means the 0th element of
+* your output corresponds to the exclusive time of function 0.
+* Two functions won't start or end at the same time.
+* Functions could be called recursively, and will always end.
+* 1 <= n <= 100
+*/
+
+public class ExclusiveTimeOfFunctions636 {
+public int[] exclusiveTime(int n, List<String> logs) {
+int[] res = new int[n];
+Stack<Integer> actives = new Stack<>();
+int preTime = 0;
+boolean preIsStart = true;
+for (String log: logs) {
+String[] strs = log.split(":");
+int id = Integer.valueOf(strs[0]);
+boolean isStart = strs[1].equals("start");
+int now = Integer.valueOf(strs[2]);
+if (isStart) {
+if (!actives.isEmpty()) {
+res[actives.peek()] += now - preTime - (preIsStart ? 0 : 1);
+}
+actives.push(id);
+} else {
+res[actives.peek()] += now - preTime + (preIsStart ? 1 : 0);
+actives.pop();
+}
+preTime = now;
+preIsStart = isStart;
+}
+return res;
+}
+
+}