【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[23][(1<<10)+5];
int Bit[23];
int a[15];
int C[(1<<10)+5];
int n;

int getBit(int x) {
    int ret = 0;
    
    while (x) {
        ret += (x & 1);
        x >>= 1;
    }
    
    return ret;
}

void Init() {
    int mst = 1<<10;
    rep(i, 0, mst)
        C[i] = getBit(i);
}

void solve() {
    rep(j, 0, 22) {
        Bit[j] = 0;
        rep(i, 0, n) {
            if (a[i] & (1<<j))
                Bit[j] |= (1<<i);
        }
    }
    
    memset(dp, INF, sizeof(dp));
    dp[0][0] = 0;
    int mst = 1<<n;
    int mask = mst - 1;
    int ans, tmp;
    
    rep(i, 0, 22) {
        rep(j, 0, mst) {
            if (dp[i][j] == INF)
                continue;
            
            int ov = j & Bit[i];
            int one = Bit[i] ^ j;
            int zero = mask & ~one;
            rep(k, 0, 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] & 1) {
                    if (val == mask)
                        continue;
                    ++tmp;
                }
                
                tmp <<= i;
                dp[i+1][k] = min(dp[i+1][k], tmp+dp[i][j]);
            }
        }
    }
            
    ans = dp[22][0];
    if (ans == INF)
        puts("impossible");
    else
        printf("%d
", 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, 0, n)
            scanf("%d", &a[i]);
        solve();
    }
    
    #ifndef ONLINE_JUDGE
        printf("time = %d.
", (int)clock());
    #endif
    
    return 0;
}

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 = 20
        bound = 10**6
        # fout.write("%d
" % (t))
        for tt in xrange(t):    
            n = randint(1, 10)
            fout.write("%d
" % (n))
            dataList = []
            for i in xrange(n):
                x = randint(1, bound)
                dataList.append(x)
            fout.write(" ".join(map(str, dataList)) + "
")
            
                
def MovDataIn():
    desFileName = "F:eclipse_prjworkspacehdojdata.in"
    shutil.copyfile("data.in", desFileName)

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