CodeforcesRound#275(Div.2)b_html/css_WEB-ITnose

/** * @brief Codeforces Round #275 (Div. 2) b * @file b.cpp * @author 面码 * @created 2014/12/11 18:09 * @edited  2014/12/11 18:09 * @type  math binary search *  * */#include #include #include #include #include #include #include #include #include using namespace std;#define max(a, b)  ((a) > (b) ? (a) : (b))#define min(a, b)  ((a) > (b) ? (b) : (a)) #define abs(a)     ((a) >  0  ? (a) : (0 - (a)))#define CLR(vec)   memset(vec, 0, sizeof(vec))#ifdef DEBUGifstream in;ofstream out;#define CIN in#define COUT out#else#define CIN cin#define COUT cout#endif#define MAXN (2e9 + 10)typedef long long int ll;ll lft, rht, mid;ll cnt1, cnt2, x, y, z;ll i, j, k;ll need1, need2;int main(void){    ios_base::sync_with_stdio(0);#ifdef DEBUG    CIN.open("./in",  ios::in);    COUT.open("./out",  ios::out);#endif    CIN >> cnt1 >> cnt2 >> x >> y;    z = x*y;    lft = 2; rht = MAXN;    while(lft <  rht){        mid = ((rht - lft)/2 + lft);                                      /*set problem*/        i = mid - mid/x;                                    j = mid - mid/y;                            k = mid -  mid/z;                      k = i + j - k;        i -= k;        j -= k;#ifdef DEBUG    COUT << i << " " << j << " " << k << "\n";#endif        if(i < cnt1)            k = k - (cnt1 - i);        if(j < cnt2)            k = k - (cnt2 - j);        if(k < 0)            lft = mid + 1;           /*need more element*/        else            rht = mid;               /*may get an answer more better*/    }    COUT << lft << endl;    return 0;}