Codeforces Round #554 (Div. 2) (A,B,C)

题目链接:http://codeforces.com/contest/1152

第一题(模拟)

#include<bits/stdc++.h>
using namespace std;

#define debug puts("YES");
#define rep(x,y,z) for(int (x)=(y);(x)<(z);(x)++)
#define ll long long

#define lrt int l,int r,int rt
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define root l,r,rt
#define mst(a,b) memset((a),(b),sizeof(a))
#define pii pair<int,int>
#define fi first
#define se second
#define mk(x,y) make_pair(x,y)
const int mod=1e9+7;
const int maxn=1e6+100;
const int ub=1e6;
ll powmod(ll x,ll y){ll t; for(t=1;y;y>>=1,x=x*x%mod) if(y&1) t=t*x%mod; return t;}
ll gcd(ll x,ll y){
    if(y==0) return x;
    return gcd(y,x%y);
}
int n,m,x;
int cnt1[2],cnt2[2];
int main(){
    cin>>n>>m;
    rep(i,0,n){
        cin>>x;
        cnt1[x%2]++;
    }
    rep(i,0,m){
        cin>>x;
        cnt2[x%2]++;
    }
    cout<<min(cnt1[0],cnt2[1])+min(cnt1[1],cnt2[0])<<endl;
    return 0;
}

第二题(位运算)

#include<bits/stdc++.h>
using namespace std;

#define debug puts("YES");
#define rep(x,y,z) for(int (x)=(y);(x)<(z);(x)++)
#define ll long long

#define lrt int l,int r,int rt
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define root l,r,rt
#define mst(a,b) memset((a),(b),sizeof(a))
#define pii pair<int,int>
#define fi first
#define se second
#define mk(x,y) make_pair(x,y)
const int mod=1e9+7;
const int maxn=1e6+100;
const int ub=1e6;
ll powmod(ll x,ll y){ll t; for(t=1;y;y>>=1,x=x*x%mod) if(y&1) t=t*x%mod; return t;}
ll gcd(ll x,ll y){
    if(y==0) return x;
    return gcd(y,x%y);
}
int x,cnt=0;
vector<int> g;
int solve(int x){
    int ret=0,cur=1;
    while(cur!=x) cur<<=1,ret++;
    return ret;
}
int main(){
    cin>>x;
    int cnt=0;
    while((x&(-x))!=x){
        int tmp=(x&-x);
        g.push_back(solve(tmp));
        x^=(tmp-1);
        x++,cnt+=2;
    }
    g.push_back(solve(x));
    cnt++;
    cout<<cnt<<endl;
    rep(i,0,g.size()) cout<<g[i]<<" ";
    return 0;
}

第三题(数论+gcd性质) 

#include<bits/stdc++.h>
using namespace std;

#define debug puts("YES");
#define rep(x,y,z) for(int (x)=(y);(x)<(z);(x)++)
#define ll long long

#define lrt int l,int r,int rt
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define root l,r,rt
#define mst(a,b) memset((a),(b),sizeof(a))
#define pii pair<int,int>
#define fi first
#define se second
#define mk(x,y) make_pair(x,y)
const int mod=1e9+7;
const int maxn=1e6+100;
const int ub=1e6;
ll powmod(ll x,ll y){ll t; for(t=1;y;y>>=1,x=x*x%mod) if(y&1) t=t*x%mod; return t;}
ll gcd(ll x,ll y){
    if(y==0) return x;
    return gcd(y,x%y);
}
ll a,b,tmp,k=0;
ll ret=1e18;
void solve(int x){
    ll p=a/x*x;
    if(p<a) p+=x;
    p-=a;
    ll ans=1LL*(a+p)*(b+p)/gcd(a+p,b+p);
    if(ans<ret){
        ret=ans;
        k=p;
    }
    if(ans==ret){
        if(p<k) k=p;
    }
}
int main(){
    cin>>a>>b;
    if(b<a) swap(a,b);
    tmp=b-a;
    for(int i=1;1LL*i*i<=tmp;i++) if(tmp%i==0){
        solve(i),solve(tmp/i);
    }
    cout<<k;
    return 0;
}