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原题见hdu5050

代码：

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <vector>
#include <map>
#include <algorithm>
#include <queue>
#include <cmath>
#include <bitset>
using namespace std;

#define INF 0x3f3f3f3f
#define ll long long int
#define ui unsigned long
#define ull unsigned long long 
#define MEM(a) memset(a, 0, sizeof(a))
#define MEMM(a) memset(b, -1, sizeof(b))
#define DBG(x, n) cout << (x) << " " << (n) << endl;

#define SL(a) strlen(a)
#define RS(s) scanf("%s", (s))
#define PI(r) printf("%d\n", (r))
#define RI(a) scanf("%d", &(a))
#define RII(a, b) scanf("%d%d", &(a), &(b))
#define RIII(a, b, c) scanf("%d%d%d", &(a), &(b), &(c))

#ifdef ONLINE_JUDGE
#define FOI(file) 0
#define FOW(file) 0
#else
#define FOI(file) freopen(file,"r",stdin);
#define FOW(file) freopen(file,"w",stdout);
#endif

#define N 1001
bitset <1001> w;
bitset <1001> h;
bitset <1001> d;

void bitsetSubtract(bitset<N> &x, const bitset<N> &y) {
    bool borrow = false;

    for (int i = 0; i < N; i++) {
        if (borrow) {
            if (x[i]) {
                x[i] = y[i];
                borrow = y[i];
            } else {
                x[i] = !y[i];
                borrow = true;
            }
        } else {
            if (x[i]) {
                x[i] = !y[i];
                borrow = false;
            } else {
                x[i] = y[i];
                borrow = y[i];
            }
        }
    }
}

bitset<N> gcd(bitset<N> u, bitset<N> v) {
    bitset<N> one (string("1"));
    bitset<N> zero (string("0"));

    int shift;

    if (u == 0) return v;
    if (v == 0) return u;

    for (shift = 0; ((u | v) & one) == zero; ++shift) {
        u >>= 1;
        v >>= 1;
    }

    while ((u & one) == zero) u >>= 1;

    do {
        while ((v & one) == zero) v >>= 1;
        string t1 = u.to_string<char, char_traits<char>, allocator<char> >();
        string t2 = v.to_string<char, char_traits<char>, allocator<char> >();

        if (t1 > t2) {
            bitset<N> t = v;
            v = u;
            u = t;
        }

        bitsetSubtract(v,u);
    } while (v != 0);

    return u << shift;
}




int main()
{
    //FOI("input");
    //FOW("output");
    //write your programme here
    
    int t;
    scanf("%d", &t);

    int i;
    int j;
    
    for(i = 1; i <= t; i++)
    {
        cin >> w >> h;
        d = gcd(w, h);
        printf("Case #%d: ", i);

        // cout << d << endl;

        j = 1000;
        while(d[j] != 1)
            j--;
        while(j != -1)
        {
            cout << d[j];
            j --;
        }
        cout << endl;
    }
    return 0;
}

hdu5050_2014ACM上海__Divided Land