The optimum range for solving HUT-XXXX digital games

This question is greedy, but here is a bit of mathematical thinking.

For the n-digit to take off K bit, then we leave is the N-K bit, we may wish to set t = n-k; so we choose the first digit after the number of T-1 let us choose, so the first number of selection range is
[1, N-T + 1], when we select the first number (assuming the position is P), we select the range of the second number is [p + 1, N-T-2, and so on. Because we want to obtain the maximum number, we select the range each time.
Use the line segment tree for optimization.

CodeAs follows:

# Include <cstdlib> # Include <Cstring> # Include <Cstdio> # Include <Algorithm> # Include <Queue> Using   Namespace  STD;  Int N, K, leave;  Char S [ 500005  ];  Struct  Node {  Int  L, R, POs, Max;} e [  2000005  ]; Vector < Int > V;  Void Push_up ( Int  P ){  If (E [P < 1 ]. Max> = E [P < 1 | 1  ]. Max) {e [p]. Max = E [P < 1  ]. Max; E [p]. Pos = E [P < 1  ]. Pos ;}  Else  {E [p]. Max = E [P < 1 | 1  ]. Max; E [p]. Pos = E [P <1 | 1  ]. Pos ;}}  Void Build ( Int P, Int L, Int  R) {e [p]. L = L, E [p]. r = R;  If (L! = R ){  Int Mid = (L + r)> 1  ; Build (P <1  , L, mid); Build (P < 1 | 1 , Mid + 1  , R); push_up (p );}  Else  {E [p]. Pos = L, E [p]. max = s [l]- '  0  '  ;  //  Initialization  }} Void Query ( Int P, Int L, Int R, Int & Rec, Int & Pos ){  If (L = E [p]. L & R = E [p]. R ){  If (REC! = E [p]. max ){  If (REC < E [p]. max) {rec = E [p]. Max; POS = E [p]. Pos ;}}  Else   If (E [p]. Pos < Pos) {pos = E [p]. Pos ;}  Return  ;}  Int Mid = (E [p]. L + E [p]. R)> 1  ;  If (R <= Mid ){ Return Query (P < 1  , L, R, REC, POS );}  Else   If (L> Mid ){  Return Query (P < 1 | 1  , L, R, REC, POS );}  Else  {Query (P < 1  , L, mid, REC, POS); query (P < 1 | 1 , Mid + 1  , R, REC, POS );}}  Int  Main (){  Int  POs, REC;  While (Scanf ( "  % D  " , & N, & K) = 2  ) {V. Clear (); POS =0  ; Scanf (  "  % S  " , S + 1 ); //  From the beginning Build ( 1 , 1  , N); leave = N-k; //  Number of remaining digits to be deleted          While (Leave ){ // Select the number of digits Rec =- 1  ; Query (  1 , POS + 1 , N-leave + 1  , REC, POS); V. push_back (REC ); -- Leave ;}  For ( Int I = 0 ; I! = ( Int ) V. Size (); ++ I) {printf ( "  % D  "  , V [I]);} puts (  ""  );}  Return   0  ;}