POJ 2429

开始闲的无聊特判gcd=1的情况 特判错了 真是呵呵诶、

我的做法 比较挫、、首先肯定对gcd 还有 lcm进行质因数Ｐｏｌｌ分解。

我是用ｍａｐ记录每个因子和出现次数。然后合并两个ｍａｐ所有质数，就是用ｍｅｒｇｅ、然后ＤＦＳ下、、去得到的ｖａｌｕｅ里面　使得　ｖａｌｕｅ＾＜＝ｇｃｄ　＊ｌｃｍ的最大ｖａｌｕｅ赋值给ａ即可。。ｂ＝　ｇｃｄ　＊　ｌｃｍ　／ａ；

#include <cstdio>#include <cstring>#include <map>#include <iterator>#include <ctime>#include <cstdlib>using namespace std;#define S 5typedef long long LL;map<LL, int>mp[2];LL gcd, lcm, ans, tot;LL factor[3000];LL mods(LL x, LL y, LL n){ x %= n;y %= n;LL tmp = 0;while(y){if(y & 1)tmp = (tmp + x) % n;x = (x << 1) % n;y >>= 1;}return tmp;}LL pow(LL x, LL y, LL n){x %= n;LL tmp = 1;while(y){if(y & 1)tmp = mods(tmp, x, n);x = mods(x, x, n);y >>= 1;}return tmp;}LL pow(LL x, LL y){LL tmp = 1;while(y){if(y & 1)tmp *= x;x *= x;y >>=1;}return tmp;}int judge(LL tmp, LL n, LL m, LL cnt){LL v = pow(tmp, m, n);LL last = v;for(LL i = 1; i <= cnt; i++){v = mods(v, v, n);if(v == 1){if(last != 1 && last != n-1)return 0;}last = v;}if(v == 1)return 1;return 0;}int miller_rubin(LL n){LL m = n - 1;LL cnt = 0;while(!(m & 1)) cnt++, m >>= 1;for(int i = 0; i < S; i++){LL tmp = (rand() % (n-1)) +1;if(!judge(tmp, n, m, cnt))return 0;}return 1;}LL f(LL x, LL n, LL c){return (mods(x, x, n) + c)%n;}LL Gcd(LL x, LL y){return y == 0?x: Gcd(y, x % y);}LL poll(LL n, LL c){if(!(n & 1))return 2;LL x = rand() % n;LL y = x;LL i = 1;LL k = 2;while(1){x = f(x, n, c);LL d = Gcd(y - x + n, n);if(d != 1 && d != n)return d;if(y == x)return n;i++;if(i == k){y = x;k += k;}}}void find(LL n, int f){if(miller_rubin(n)){mp[f][n]++;return;}LL p = n;while(p >= n) p = poll(p, rand()%(n-1) + 1);find(p, f);find(n / p, f);}void dfs(int i, LL sum){if(i >= tot){if(lcm / sum >= sum / gcd)if(sum > ans)ans = sum;return; }for(int j = 0; j < 2; j++){dfs(i+1, sum * pow(factor[i], mp[j][factor[i]]));}}int main(){srand(time(NULL));while(scanf("%lld%lld", &gcd, &lcm)!=EOF){mp[0].clear();mp[1].clear();if( gcd == lcm){printf("%lld %lld\n",gcd,lcm);continue;}ans = 0;tot = 0;if(gcd != 1)find(gcd,0);if(lcm != 1)find(lcm,1);map<LL,int>::iterator it1 = mp[0].begin(), it2 = mp[1].begin();while(it1 != mp[0].end() && it2 != mp[1].end()){if(it1->first == it2->first){factor[tot++] = it1->first;++it1;++it2;}elseif(it1->first > it2->first){factor[tot++] = it2->first;++it2;}else{factor[tot++] = it1->first;++it1;}}while(it1 != mp[0].end()){factor[tot++]=it1->first;++it1;}while(it2 != mp[1].end()){factor[tot++]=it2->first;++it2;}dfs(0, 1);printf("%lld %lld\n", ans,lcm / ans * gcd); }return 0;}