策略
1. 序列問題
題意: 給定一個序列,若y = x * P, 則稱這兩個元素是互斥的,求一個任意兩元素皆不互斥的最長序列元素個數。
算法: ?對每一個數,可選擇要與不要, 然后衡量要與不要的代價,然后做出選擇。
代碼:?
View Code #include <stdlib.h> #include <string.h> #include <algorithm> #include <map> using namespace std;int a[100100]; int N,P; long long maxn; map<int,int>mp; map<int,int>HASH;int getval(int x) //取X {int ans = mp[x], num = 1;long long mul = x * P;while( mul <= maxn ){ if( mp.find(mul) == mp.end() ) //如果沒有找到這個數 return ans;if( num & 1 ) //如果不要ans -= mp[mul], ++num;elseans += mp[mul], ++num;mul *= P; if( P == 1 )break;}return ans; } int getmodi(int x) //取X {int ans = mp[x], num = 1;long long mul = x * P;while( mul <= maxn ){ if( mp.find(mul) == mp.end() ) //如果沒有找到這個數 return ans;if( num & 1 ) //如果不要HASH[mul] = 1,++num;elseans += mp[mul], ++num, HASH[mul] = 1;mul *= P; if( P == 1 )break;}return ans; }int ungetmodi(int x) //不取X {int ans = 0, num = 1;long long mul = x * P;while( mul <= maxn ){ if( mp.find(mul) == mp.end() ) //如果沒有找到這個數 return ans;if( num & 1 ) //如果不要ans += mp[mul], ++num, HASH[mul] = 1;elseHASH[mul] = 1,++num;mul *= P; if( P == 1 )break;}return ans; }int ungetval(int x) //不取X {int ans = 0, num = 1;long long mul = x * P;while( mul <= maxn ){ if( mp.find(mul) == mp.end() ) return ans;if( num & 1 ) ans += mp[mul], ++num;elseans -= mp[num], ++num;mul *= P; if( P == 1 )break;}return ans; }int main( ) {while( scanf("%d%d",&N,&P) != EOF){mp.clear();HASH.clear();maxn = 0;for(int i = 0; i < N; ++i){scanf("%d",&a[i]);++mp[a[i]];//printf("%d\n",mp[a[i]]);if( a[i] >= maxn )maxn = a[i]; }map<int,int>::iterator it = mp.begin();int ans = 0;for( ; it != mp.end(); ++it){if( HASH[it->first] != 1 ){int c1 = getval(it->first);int c2 = ungetval(it->first);//printf("val = %d %d %d\n",it->first, c1,c2);if( c1 >= c2 ) //當前數加入互斥集合 {ans += getmodi(it->first); }else{ans += ungetmodi(it->first); }}}printf("%d\n",ans); }return 0; }?
轉載于:https://www.cnblogs.com/lucky-boy/archive/2013/03/26/2982693.html
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