先看一下我暴力的代码:
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#include <bits/stdc++.h>
using namespace std;
#define clr(s, x) memset(s, x, sizeof(s))
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
inline int read(){int r=0;char c=getchar();while(c<'0'||c>'9') {c=getchar();}while(c>='0'&&c<='9') {r=r*10+c-'0';c=getchar();}return r;}
inline ll readll(){ll r=0;char c=getchar();while(c<'0'||c>'9') {c=getchar();}while(c>='0'&&c<='9') {r=r*10+c-'0';c=getchar();}return r;}
inline ll qpow(ll a,ll b,ll mod){ll res=1;while(b){if(b&1)res = (res*a)%mod;a=(a*a)%mod;b>>=1;}return res;}
inline ll gcd(ll a,ll b){while(b^=a^=b^=a%=b);return a;}
const double eps = 1e-8;
const ll LLINF = 0x3f3f3f3f3f3f3f3f;
const int INF = 0x3f3f3f3f;
const int mod = 1e9+7;
const int MAXN = 1e5;
const int MAXM = 1e5;
int dp[10], p;
void solve(int res){
if(res == 1){
dp[1] = min(dp[1], dp[0] + p);
dp[3] = min(dp[3], dp[2] + p);
dp[5] = min(dp[5], dp[4] + p);
dp[7] = min(dp[7], dp[6] + p);
} else if(res == 2){
dp[2] = min(dp[2], dp[0] + p);
dp[3] = min(dp[3], dp[1] + p);
dp[6] = min(dp[6], dp[4] + p);
dp[7] = min(dp[7], dp[5] + p);
} else if(res == 3){
dp[3] = min(dp[3], dp[0] + p);
dp[7] = min(dp[7], dp[4] + p);
} else if(res == 4){
dp[4] = min(dp[4], dp[0] + p);
dp[5] = min(dp[5], dp[1] + p);
dp[6] = min(dp[6], dp[2] + p);
dp[7] = min(dp[7], dp[3] + p);
} else if(res == 5){
dp[5] = min(dp[5], dp[0] + p);
dp[7] = min(dp[7], dp[2] + p);
} else if(res == 6){
dp[6] = min(dp[6], dp[0] + p);
dp[7] = min(dp[7], dp[1] + p);
} else if(res == 7){
dp[7] = min(dp[7], dp[0] + p);
}
}
int main(int argc, char const *argv[])
{
ios::sync_with_stdio(false);
int n;
while(cin >> n){
int res;
string s;
clr(dp, 0x3f);
dp[0] = 0;
for(int i=1; i<=n; ++i){
cin >> p;
cin >> s;
res = 0;
if((int)s.find('A') != -1) res+=1;
if((int)s.find('B') != -1) res+=2;
if((int)s.find('C') != -1) res+=4;
if(res == 1){
solve(1);
} else if(res == 2){
solve(2);
} else if(res == 3){
solve(1);
solve(2);
solve(3);
} else if(res == 4){
solve(4);
} else if(res == 5){
solve(1);
solve(4);
solve(5);
} else if(res == 6){
solve(2);
solve(4);
solve(6);
} else if(res == 7){
solve(1);
solve(2);
solve(3);
solve(4);
solve(5);
solve(6);
solve(7);
}
// cout << dp[7] << endl;
}
if(dp[7] >= INF) puts("-1");
else cout << dp[7] << endl;
}
return 0;
}
看完应该就知道思路了,然后我们用二进制枚举来做:
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#include <bits/stdc++.h>
using namespace std;
#define clr(s, x) memset(s, x, sizeof(s))
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
inline int read(){int r=0;char c=getchar();while(c<'0'||c>'9') {c=getchar();}while(c>='0'&&c<='9') {r=r*10+c-'0';c=getchar();}return r;}
inline ll readll(){ll r=0;char c=getchar();while(c<'0'||c>'9') {c=getchar();}while(c>='0'&&c<='9') {r=r*10+c-'0';c=getchar();}return r;}
inline ll qpow(ll a,ll b,ll mod){ll res=1;while(b){if(b&1)res = (res*a)%mod;a=(a*a)%mod;b>>=1;}return res;}
inline ll gcd(ll a,ll b){while(b^=a^=b^=a%=b);return a;}
const double eps = 1e-8;
const ll LLINF = 0x3f3f3f3f3f3f3f3f;
const int INF = 0x3f3f3f3f;
const int mod = 1e9+7;
const int MAXN = 1e5;
const int MAXM = 1e5;
int dp[10], p;
void solve(int res){
for(int i=1; i<=7; ++i){
bool flag = 1;
for(int j=0; j<=2; ++j){
if(((res>>j)&1) && !((i>>j)&1)) flag = 0;
}
if(flag) dp[i] = min(dp[i], dp[i-res] + p);
}
}
int main(int argc, char const *argv[])
{
ios::sync_with_stdio(false);
int n;
while(cin >> n){
int res;
string s;
clr(dp, 0x3f);
dp[0] = 0;
for(int i=1; i<=n; ++i){
cin >> p;
cin >> s;
res = 0;
if((int)s.find('A') != -1) res+=1;
if((int)s.find('B') != -1) res+=2;
if((int)s.find('C') != -1) res+=4;
// cout << res << endl;
for(int i=1; i<=7; ++i){
bool flag = 1;
for(int j=0; j<=2; ++j){
if(((i>>j)&1) && !((res>>j)&1)){
flag = 0;
}
}
if(flag) solve(i);
}
// cout << dp[7] << endl;
}
if(dp[7] >= INF) puts("-1");
else cout << dp[7] << endl;
}
return 0;
}
就酱~