Trapping Rain Water

Use the stack structure to resolve.

#include <iostream>#include<stack>using namespacestd;classSolution { Public:    intTrapintA[],intN) {
        if(n<3){            return 0; }
Stack<int>Water_stack; intbegin=0; intres=0;
         for(inti =0; i<n;++i) {            if(a[i]>0&&Water_stack.empty ())                {Water_stack.push (a[i]); Begin=A[i]; Continue; }            if(a[i]<begin)                {Water_stack.push (a[i]); Continue; }            if(A[i]>=begin && begin!=0){                 while(!Water_stack.empty ()) {                    //cout<< "A" <<i<< ":" <<A[i]; //cout<< "begin:" <<begin; //cout<< "Top:" <<water_stack.top () <<endl;Res+=begin-Water_stack.top ();                Water_stack.pop ();                } water_stack.push (A[i]); Begin=A[i]; }            //cout<< "Res:" <<res<<endl;        }
        intEnd=0;  while(!Water_stack.empty ()) {            if(Water_stack.top () >=end) {End=Water_stack.top ();            Water_stack.pop (); }            Else{res+=end-Water_stack.top ();            Water_stack.pop (); }        }
        returnRes; }};intMainintargcChar**argv)    {solution S; inta[]={0,1,0,2,1,0,1,3,2,1,2,1}; cout<<s.trap (A, A); return 0;}

Writing is not perfect, it seems to use the stack and stack, in fact, no stack can be solved.

Trapping Rain Water