// help from community to have effective algorithm //https://www.sololearn.com/Discuss/2656563/?ref=app #include #include #include using namespace std; stack reverseStack(stack s) { stack revStack; while(!s.empty()) { revStack.push(s.top()); s.pop(); } return revStack; } int minInStack(stack s) { int min = INT_MAX; while(!s.empty()) { if(s.top() < min) { min = s.top(); } s.pop(); } return min; } void popAndMin(stack s) { while(!s.empty()) { cout << minInStack(s) << " "; s.pop(); } cout << endl; } void popAndMin_Effective(stack& s) { s = reverseStack(s); stacktmpStack; stackminStack; while(!s.empty()) { int elem = s.top(); tmpStack.push(elem); // if min stack is empty, push the given element into it if (minStack.empty()) { minStack.push(elem); } else { // push the given element into the min stack if it is less than or equal to the current minimum if (minStack.top() >= elem) { minStack.push(elem); } } //main s stack pop to break the loop of while s.pop(); } while(!tmpStack.empty()) { int min = minStack.top(); int elem = tmpStack.top(); //print minimum elem cout << min << " "; // remove top element from the temp stack tmpStack.pop(); // remove top element from the min stack only if cur elem is minimum if (elem == min) { minStack.pop(); } } } int main() { stack s; s.push(2); s.push(1); s.push(3); s.push(0); s.push(5); popAndMin(s); popAndMin_Effective(s); return 0; }

Stack_Min