Codeforces Round #543 (Div. 2, based on Technocup 2019 Final Round)

A

签到

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int maxn = 150;
int p[maxn],s[maxn],mx[maxn],c[maxn];
int main() {
    int n,m,k;
    cin>>n>>m>>k;
    for(int i = 1;i <= n;i++){
        cin>>p[i];
    }
    for(int i = 1;i <= n;i++){
        cin>>s[i];
    }
    for(int i = 1;i <= n;i++){
        if(p[mx[s[i]]] < p[i]){
            mx[s[i]] = i;
        }
    }
    int tot = 0;
    for(int i = 1;i <= k;i++){
        cin>>c[i];
        if(mx[s[c[i]]] != c[i]) tot++;
    }
    cout<<tot;
    return 0;
}

B

签到

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int maxn = 1050;
const int maxm = 200050;
int a[maxn],vis[maxm];
int main() {
    int n;
    cin>>n;
    for(int i = 1;i <= n;i++){
        cin>>a[i];
    }
    int ans = 0;
    for(int i = 1;i <= n;i++){
        for(int j = i+1;j <= n;j++){
            vis[a[i]+a[j]]++;
            ans = max(vis[a[i]+a[j]],ans);
        }
    }
    cout<<ans;
    return 0;
}

C

模拟

#include<bits/stdc++.h>
using namespace std;
int n,k,i,j,m,l,b[150],c[150],a[1500],d[1500],f[1500];
int main()
{
    for(scanf("%d%d",&n,&k); i<n; ++i,scanf("%d",a+i));
    for(m=-(k=min(k,n)); m<n;)
    {
        for(i=1; i<=k; (c[i]==a[b[i]]?(b[i]=j,d[j]=c[i]=1,++m):++c[i]),++i)
            if(c[i]==a[b[i]])
                for(j=1; j<=n&&d[j]; ++j);
        for(l=(200*m+n)/(n<<1),i=1; i<=k; f[b[i]]|=(c[i]==l),++i);
    }
    for(k=0,i=1; i<=n; k+=f[i++]);
    printf("%d\n",k),exit(0);
}

D

尺取法，剪裁区间细节很多

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int maxn = 500050;
int m,n,k,s;
int a[maxn],b[maxn];
int t[maxn];
int now[maxn];
bool vis[maxn];
int main() {
    ios::sync_with_stdio(false);
    cin>>m>>k>>n>>s;
    for(int i = 1;i <= m;i++) {
        cin >> a[i];
    }
    for(int i = 1;i <= s;i++){
        cin>>b[i];
        t[b[i]]++;
    }
    if(s > k){
        cout<<-1;
        return 0;
    }
    int lp = 1;
    int wst = 0;
    int ansl = 0,ansr = 0,ans = maxn;
    int cnt=0;
    int lm = m - n*k;
    for(int j = 1;j <= m;j++){
        if(!t[a[j]]){
            wst++;
        }else{
            if(now[a[j]] < t[a[j]])cnt++;
            else wst++;
            now[a[j]]++;
        }
        while(now[a[lp]] > t[a[lp]] || !t[a[lp]]){
            if(lp > j) break;
            if(!t[a[lp]]){
                wst--;
                lp++;
            }else{
                now[a[lp]]--;
                wst--;
                lp++;
            }
        }
        if(cnt == s){
            int tl = lp;
            int tr = j;
            int tw = max(tr-tl+1-k,0);
            //int cut = wst + min(tr%k,(tl-1)%k);
            int cut = min((tl-1)%k+tw,tw+(tr-tw)%k);
            if(cut <= lm){
                ansl = lp;
                ansr = j;
                ans = cut;
            }
        }
    }
    if(ans > lm) cout<<"-1";
    else{
        memset(now,0,sizeof(now));
        cout<<m-n*k<<endl;
        int tt = m-n*k;
        for(int i = ansl;i <= ansr;i++){
            if(tt <= 0) break;
            now[a[i]]++;
            if(now[a[i]] > t[a[i]]){
                vis[i] = true;
                tt--;
            }
        }
        for(int i = ansl-1;i >= 1 && tt > 0;i--,tt--){
            vis[i] = true;
        }
        for(int i = ansr+1;i <= m && tt > 0;i++,tt--){
            vis[i] = true;
        }
        for(int i = 1;i <= m;i++){
            if(vis[i]) cout<<i<<" ";
        }
        cout<<endl;
    }
    return 0;
}

F

DP

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int maxn = 5050;
char s[maxn];
int n,a,b;
int dp[maxn];
int f[maxn][maxn];
int main() {
    ios::sync_with_stdio(false);
    cin>>n>>a>>b;
    cin>>(s+1);
    for(int i = 2;i <= n;i++){
        for(int j = 1;j < i;j++){
            if(s[i] == s[j]) f[i][j] = f[i-1][j-1] + 1;
        }
    }
    for(int i = 1;i <= n;i++){
        dp[i] = min(a*i,dp[i-1]+a);
        for(int j = 1;j < i;j++){
            dp[i] = min(dp[i],dp[i-min(i-j,f[i][j])]+b);
        }
    }
    cout<<dp[n];
    return 0;
}