add new solutions

solutions/1/q155/solution.go

@@ -0,0 +1,44 @@
+package q155
+
+type stackElem struct {
+	val, min int
+}
+
+type MinStack struct {
+	stack []stackElem
+}
+
+func Constructor() MinStack {
+	return MinStack{}
+}
+
+func (s *MinStack) Push(val int) {
+	minVal := val
+	if len(s.stack) > 0 {
+		minVal = min(minVal, s.GetMin())
+	}
+	s.stack = append(s.stack, stackElem{
+		val: val, min: minVal,
+	})
+}
+
+func (s *MinStack) Pop() {
+	s.stack = s.stack[:len(s.stack)-1]
+}
+
+func (s *MinStack) Top() int {
+	return s.stack[len(s.stack)-1].val
+}
+
+func (s *MinStack) GetMin() int {
+	return s.stack[len(s.stack)-1].min
+}
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * obj := Constructor();
+ * obj.Push(val);
+ * obj.Pop();
+ * param_3 := obj.Top();
+ * param_4 := obj.GetMin();
+ */