diff --git a/Lesson-2/assignment/yours.sol b/Lesson-2/assignment/yours.sol
index dfdb2c4..5e24777 100644
--- a/Lesson-2/assignment/yours.sol
+++ b/Lesson-2/assignment/yours.sol
@@ -1 +1,100 @@
 /*作业请提交在这个目录下*/
+pragma solidity ^0.4.14;
+
+contract Payroll {
+    struct Employee {
+        address id;
+        uint salary;
+        uint lastPayday;
+    }
+
+    uint constant payDuration = 10 seconds;
+
+    address owner;
+    Employee[] employees;
+
+    uint totalSalary;
+
+    function Payroll() {
+        owner = msg.sender;
+    }
+
+    function _partialPaid(Employee employee) private {
+      uint payment = employee.salary * (now - employee.lastPayday) / payDuration;
+      employee.id.transfer(payment);
+    }
+
+    function _calculatePayment(Employee employee) private returns (uint){
+        uint payment = employee.salary * (now - employee.lastPayday) / payDuration;
+        return payment;
+    }
+
+    function _findEmployee(address employeeId) private returns (Employee, uint) {
+        for(uint i = 0; i < employees.length; i++){
+          if(employees[i].id == employeeId){
+            return (employees[i], i);
+          }
+        }
+    }
+
+    function addEmployee(address employeeId, uint salary) {
+        require(msg.sender == owner);
+        var(employee, index)  = _findEmployee(employeeId);
+        assert(employee.id == 0x0);
+        totalSalary +=salary;
+        employees.push(Employee(employeeId, salary, now));
+    }
+
+    function removeEmployee(address employeeId) {
+        require(msg.sender == owner);
+        var (employee, index) = _findEmployee(employeeId);
+        assert(employee.id != 0x0);
+
+        uint payment = _calculatePayment(employee);
+        
+
+        totalSalary -= employees[index].salary;
+        delete employees[index];
+        employees.length -= 1;
+        employeeId.transfer(payment);
+
+
+    }
+
+    function updateEmployee(address employeeId, uint salary) {
+       require(msg.sender == owner);
+       var(employee, index) = _findEmployee(employeeId);
+       assert(employee.id != 0x0);
+       uint payment = _calculatePayment(employee);
+
+       /* _partialPaid(employee); */
+
+       totalSalary += salary - employees[index].salary;
+       employees[index].salary = salary;
+       employees[index].lastPayday = now;
+       employeeId.transfer(payment);
+
+    }
+
+    function addFund() payable returns (uint) {
+       return this.balance;
+    }
+
+    function calculateRunway() returns (uint) {
+        return this.balance / totalSalary;
+    }
+
+    function hasEnoughFund() returns (bool) {
+      return calculateRunway() > 0;
+    }
+
+    function getPaid() {
+        var (employee, index) = _findEmployee(msg.sender);
+        require(employee.id != 0x0);
+
+        uint nextPayDay = employee.lastPayday + payDuration;
+        assert(nextPayDay < now);
+
+        employees[index].lastPayday = nextPayDay;
+        employees[index].id.transfer(employee.salary);
+    }