Codeforces Round #539 (Div. 2)
#include<bits/stdc++.h> #include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<cmath> #include<algorithm> #include<queue> #include<vector> #include<map> #define lson i<<1 #define rson i<<1|1 #define LS l,mid,lson #define RS mid+1,r,rson #define mem(a,x) memset(a,x,sizeof(a)) #define gcd(a,b) __gcd(a,b) #define ll long long #define ull unsigned long long #define lowbit(x) (x&-x) #define pb(x) push_back(x) #define enld endl #define mian main #define itn int #define prinft printf #pragma GCC optimize(2) //#pragma comment(linker, "/STACK:102400000,102400000") const double PI = acos (-1.0); const int INF = 0x3f3f3f3f; ; ; ; ; using namespace std; int n,v; int main() { cin>>n>>v; <=v) { cout<<n-<<endl; ; } int ans=v; ;i<=n--v+;++i) ans+=i; cout<<ans<<endl; }
A - Sasha and His Trip
B - Sasha and Magnetic Machines
#include<bits/stdc++.h> #include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<cmath> #include<algorithm> #include<queue> #include<vector> #include<map> #define lson i<<1 #define rson i<<1|1 #define LS l,mid,lson #define RS mid+1,r,rson #define mem(a,x) memset(a,x,sizeof(a)) #define gcd(a,b) __gcd(a,b) #define ll long long #define ull unsigned long long #define lowbit(x) (x&-x) #define pb(x) push_back(x) #define enld endl #define mian main #define itn int #define prinft printf #pragma GCC optimize(2) //#pragma comment(linker, "/STACK:102400000,102400000") const double PI = acos (-1.0); const int INF = 0x3f3f3f3f; ; ; ; ; using namespace std; ],n,sum,tmp,Min; vector<int> p; void init() { mem(vis,),sum=,Min=INF; } void Solve(int n) { p.clear(); ; i<=n; i++) { ) { p.push_back(i); } } } int main() { init(); scanf("%d",&n); ; i<=n; ++i) { scanf("%d",&tmp); sum+=tmp; vis[tmp]=; Min=min(Min,tmp); } int ans=sum; ; i<=; ++i) if(vis[i]) { Solve(i); ) continue; ; j<p.size(); ++j) { ans=min(ans,sum-(i-i/p[j])+Min*p[j]-Min); // cout<<j<<' '<<p[j]<<endl; } } cout<<ans<<endl; }
B - Sasha and Magnetic Machines
1、交换律
2、结合律(即(a^b)^c == a^(b^c))
3、对于任何数x,都有x^x=0,x^0=x
4、自反性 A XOR B XOR B = A xor 0 = A
前缀异或