【HDOJ】4317 Unfair Nim

基本的状态压缩，想明白怎么dp还是挺简单的。
显然对n个数字进行状态压缩，dp[i][j]表示第i位状态j表示的位向高位产生了进位。

 /* 4317 */
 #include <iostream>
 #include <sstream>
 #include <string>
 #include <map>
 #include <queue>
 #include <set>
 #include <stack>
 #include <vector>
 #include <deque>
 #include <algorithm>
 #include <cstdio>
 #include <cmath>
 #include <ctime>
 #include <cstring>
 #include <climits>
 #include <cctype>
 #include <cassert>
 #include <functional>
 #include <iterator>
 #include <iomanip>
 using namespace std;
 //#pragma comment(linker,"/STACK:102400000,1024000")

 #define sti                set<int>
 #define stpii            set<pair<int, int> >
 #define mpii            map<int,int>
 #define vi                vector<int>
 #define pii                pair<int,int>
 #define vpii            vector<pair<int,int> >
 #define rep(i, a, n)     for (int i=a;i<n;++i)
 #define per(i, a, n)     for (int i=n-1;i>=a;--i)
 #define clr                clear
 #define pb                 push_back
 #define mp                 make_pair
 #define fir                first
 #define sec                second
 #define all(x)             (x).begin(),(x).end()
 #define SZ(x)             ((int)(x).size())
 #define lson            l, mid, rt<<1
 #define rson            mid+1, r, rt<<1|1

 const int INF = 0x3f3f3f3f;
 int dp[][(<<)+];
 int Bit[];
 int a[];
 int C[(<<)+];
 int n;

 int getBit(int x) {
     int ret = ;

     while (x) {
         ret += (x & );
         x >>= ;
     }

     return ret;
 }

 void Init() {
     int mst = <<;
     rep(i, , mst)
         C[i] = getBit(i);
 }

 void solve() {
     rep(j, , ) {
         Bit[j] = ;
         rep(i, , n) {
             if (a[i] & (<<j))
                 Bit[j] |= (<<i);
         }
     }

     memset(dp, INF, sizeof(dp));
     dp[][] = ;
     int mst = <<n;
     int mask = mst - ;
     int ans, tmp;

     rep(i, , ) {
         rep(j, , mst) {
             if (dp[i][j] == INF)
                 continue;

             int ov = j & Bit[i];
             int one = Bit[i] ^ j;
             int zero = mask & ~one;
             rep(k, , mst) {
                 if (ov & ~k)
                     continue;

                 int other_ov = k & ~ov;
                 if (other_ov & zero)
                     continue;

                 tmp = C[other_ov];
                 int val = one ^ other_ov;
                 if (C[val] & ) {
                     if (val == mask)
                         continue;
                     ++tmp;
                 }

                 tmp <<= i;
                 dp[i+][k] = min(dp[i+][k], tmp+dp[i][j]);
             }
         }
     }

     ans = dp[][];
     if (ans == INF)
         puts("impossible");
     else
         printf("%d\n", ans);
 }

 int main() {
     ios::sync_with_stdio(false);
     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     Init();
     while (scanf("%d", &n)!=EOF) {
         rep(i, , n)
             scanf("%d", &a[i]);
         solve();
     }

     #ifndef ONLINE_JUDGE
         printf("time = %d.\n", (int)clock());
     #endif

     return ;
 }

数据发生器。

 from copy import deepcopy
 from random import randint, shuffle
 import shutil
 import string

 def GenDataIn():
     with open("data.in", "w") as fout:
         t =
         bound = **
         # fout.write("%d\n" % (t))
         for tt in xrange(t):
             n = randint(, )
             fout.write("%d\n" % (n))
             dataList = []
             for i in xrange(n):
                 x = randint(, bound)
                 dataList.append(x)
             fout.write(" ".join(map(str, dataList)) + "\n")

 def MovDataIn():
     desFileName = "F:\eclipse_prj\workspace\hdoj\data.in"
     shutil.copyfile("data.in", desFileName)

 if __name__ == "__main__":
     GenDataIn()
     MovDataIn()