Leetcode 232. Implement Queue using Stacks

Similar to 225, the queue and stack are of the opposite nature, so they are processed at push.

Maintain two STACK:STK and TMP,STK in the opposite order of queue, such as queue: 1, 4, 5,STK: 5, 4, 1, so stk.top () will always be equal to Queue.front ().

Each push into a number x, the number of STK within the full push into the TMP, and then the X into the STK, and finally the number of TMP in the full push into STK, so that the x at the bottom of Stk.

1 classQueue {2  Public:3     //Push element x to the back of the queue.4     voidPushintx) {5          while(!Stk.empty ()) {6 Tmp.push (Stk.top ());7 Stk.pop ();8         }9 Stk.push (x);Ten          while(!Tmp.empty ()) { One Stk.push (Tmp.top ()); A Tmp.pop (); -         } -     } the  -     //Removes the element from in front of the queue. -     voidPopvoid) { - Stk.pop (); +     } -  +     //Get the front element. A     intPeekvoid) { at         returnstk.top (); -     } -  -     //Return Whether the queue is empty. -     BOOLEmptyvoid) { -         returnstk.empty (); in     } - Private: tostack<int>STK, TMP; +};

Leetcode 232. Implement Queue using Stacks