Uoj #2 "NOI2014" Get up difficulty syndrome greedy + bitwise arithmetic

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Given the number of n, each number has a specific operation, &|^ three, give a m, the initial value belongs to [0,m], select an initial value, so that all operations done after the value of the largest, output this maximum value.

1, from the highest bit greedy, if the initial this bit is 0, when all operations are finished after the result is 1, then this bit has determined bit 0.

2, initially 0, if this bit is 0 after all operations have been completed, then try the initial condition of 1. Set the current bit is the POS bit, if the previous number plus (1<<pos) is less than m, then this bit is 1 is possible. When the initial is 1, after all operations have been completed, if 1, then this bit is determined to be 1, otherwise this bit is 0.

See the code specifically.

#include <iostream>#include<vector>#include<cstdio>#include<cstring>#include<algorithm>#include<cmath>#include<map>#include<Set>#include<string>#include<queue>#include<stack>#include<bitset>using namespacestd;#definePB (x) push_back (x)#definell Long Long#defineMK (x, y) make_pair (x, y)#defineLson L, M, rt<<1#defineMem (a) memset (a, 0, sizeof (a))#defineRson m+1, R, rt<<1|1#defineMem1 (a) memset (a,-1, sizeof (a))#defineMEM2 (a) memset (a, 0x3f, sizeof (a))#defineRep (i, N, a) for (int i = A; i<n; i++)#defineFi first#defineSe Secondtypedef pair<int,int>PLL;Const DoublePI = ACOs (-1.0);Const DoubleEPS = 1e-8;Const intMoD = 1e9+7;Const intINF =1061109567;Const intdir[][2] = { {-1,0}, {1,0}, {0, -1}, {0,1} };intM, ans, N, digit[100005][ +];Charc[100005][4];voidCalintNumintflag) {    intx =0;  for(inti =0; i<n; i++) {        if(c[i][0] =='A') {x&=Digit[i][num]; } Else if(c[i][0] =='O') {x|=Digit[i][num]; } Else{x^=Digit[i][num]; }    }    if(x) {ans+= (1<<num); return ; }    if(flag) {x=1;  for(inti =0; i<n; i++) {            if(c[i][0] =='A') {x&=Digit[i][num]; } Else if(c[i][0] =='O') {x|=Digit[i][num]; } Else{x^=Digit[i][num]; }        }        if(x = =1) {ans+= (1<<num); M-= (1<<num); }    }}intMain () {intx; CIN>>n>>m;  for(inti =0; i<n; i++) {scanf ("%s%d", C[i], &x); intnum =0;  while(x) {Digit[i][num+ +] = x&1; X>>=1; }    }     for(inti = -; i>=0; i--) {        intFlag =0; if((1<<i) <=m) Flag=1;    Cal (I, flag); } cout<<ans<<Endl; return 0;}

Uoj #2 "NOI2014" Get up difficulty syndrome greedy + bitwise arithmetic