AcWing《蓝桥杯集训·每日一题》拼团优惠！https://www.acwing.com/activity/content/introduction/2869/group_buy/134085/

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

int main(){
    int n,k;
    scanf("%d %d",&n,&k);
    int tmp=n/k;
    printf("%d",k*tmp+k);
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
const int N=(1<<20)+10;
int st[N],primes[N],minp[N];
int cnt;
typedef long long ll;
ll f[21];
void get_primes(int n){
    for(int i=2;i<=n;i++){
        if(!st[i]){
            minp[i]=i;
            primes[cnt++]=i;
            st[i]=1;
        }
        for(int j=0;i*primes[j]<n;j++){
            st[i*primes[j]]=1;
            minp[i*primes[j]]=primes[j];
            if(i%primes[j]==0)break;
        }
    }
}
int main(){
    f[1]=1;
    for(int i=2;i<21;i++){
        f[i]=f[i-1]*i;
    }
    int x;
    get_primes(N-1);
    while(cin>>x){
        ll sum=1;
        ll total=0;
        while(x>1){
            int p=minp[x];
            int k=0;
            while(x%p==0)   
            {
                k++;
                total++;
                x/=p;
            }
            sum*=f[k];
        }
        printf("%lld %lld\n",total,f[total]/sum);
    }
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
const int N=100010;
int a[N];
int main(){
    int n;
    cin>>n;
    for(int i=0;i<n;i++)scanf("%d",&a[i]);
    sort(a,a+n);
    int select;
    select=n/2;
    int ans=0;
    for(int i=0;i<n;i++){
        int t=abs(a[select]-a[i]);
        //cout<<t<<endl;
        ans+=t;
    }
    cout<<ans;
    return 0;
}

// #include<bits/stdc++.h>
// using namespace std;
// //f[i][j][k][v]走到(i,j)处时，所有宝物的最大价值v以及件数k
// int main(){
//     cin>>n>>m>>k;//n行m列k件

//     return 0;
// }
#include <iostream>
#include <algorithm>

using namespace std;

const int N = 55;
const int M = 15;
const int MOD = 1e9 + 7;

int n, m, c;
int a[N][N];
int f[N][N][M][M];

int main(){

    scanf("%d%d%d", &n, &m, &c);
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++){
            scanf("%d", &a[i][j]);
            a[i][j]++;
        }
    f[1][1][0][0] = 1;
    f[1][1][1][a[1][1]] = 1;

    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
            for(int cnt = 0; cnt <= c; cnt++)
                for(int k = 0; k < M; k++){
                    //不拿物品
                    f[i][j][cnt][k] = (f[i][j][cnt][k] + f[i - 1][j][cnt][k]) % MOD;
                    f[i][j][cnt][k] = (f[i][j][cnt][k] + f[i][j - 1][cnt][k]) % MOD;

                    //可以拿
                    if(cnt > 0 && k == a[i][j]){
                        for(int s = 0; s < a[i][j]; s++){
                            f[i][j][cnt][k] = (f[i][j][cnt][k] + f[i - 1][j][cnt - 1][s]) % MOD;
                            f[i][j][cnt][k] = (f[i][j][cnt][k] + f[i][j - 1][cnt - 1][s]) % MOD;
                        }
                    }
                }
    int res = 0;
    for(int i = 1; i < M; i++)
        res = (res + f[n][m][c][i]) % MOD;

    printf("%d\n", res);

    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int a[100010];
int gcd(int a,int b){
    return b?gcd(b,a%b):a;
}
int main(){
    int n;
    cin>>n;
    for(int i=0;i<n;i++)scanf("%d",&a[i]);
    sort(a,a+n);
    int d=0;
    for(int i=1;i<n;i++){
        d=gcd(d,a[i]-a[0]);
    }
    if(d==0)cout<<n;
    else cout<<(a[n-1]-a[0])/d+1;
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
// #define x first
// #define y second
const int N = 105;
struct point {
    int x, y, z;
    int step;
};
int l, r, c;
point start, endd;
char g[N][N][N];
int v[N][N][N];
int bfs() {
    int ans = 0;
    memset(v, 0, sizeof v);
    queue<point>p;
    int dx[6] = { -1,1,0,0,0,0 };
    int dy[6] = { 0,0,-1,1,0,0 };
    int dz[6] = { 0,0,0,0,1,-1 };
    v[start.z][start.x][start.y] = 1;
    start.step = 0;
    p.push(start);
    while (p.size()) {
        point t = p.front();
        for (int i = 0; i < 6; i++) {
            int x = dx[i] + t.x, y = dy[i] + t.y, z = dz[i] + t.z;
            //cout << x << "-" << y << "-" << z << endl;
            if (x < 0 || y < 0 || z<0 || x >= r || y >= c || z>l)continue;
            if (v[z][x][y])continue;
            if (g[z][x][y] == '.'||(x == endd.x && y == endd.y && z == endd.z)) {
                point temp;
                temp.x = x; temp.y = y; temp.z = z; temp.step = t.step + 1;
                v[z][x][y] = 1;
                p.push(temp);
                //cout << p.size() << endl;
                if (x == endd.x && y == endd.y && z == endd.z)return temp.step;
                //ans++;
            }
            else {
                continue;
            }
        }
        p.pop();
    }
    return -1;
}
int main() {
    //cin>>l>>r>>c;
    while (scanf("%d%d%d", &l, &r, &c) && r && c && l) {

        int x = l;
        while (x) {
            for (int i = 0; i < r; i++)scanf("%s", g[x][i]);
            for (int i = 0; i < r; i++)
                for (int j = 0; j < c; j++) {
                    if (g[x][i][j] == 'S') { start.x = i, start.y = j; start.z = x; }
                    if (g[x][i][j] == 'E') { endd.x = i, endd.y = j; endd.z = x; }
                }
            x--;
        }
        //cout << "1" << endl;
        //cout<<g[2][1][0]<<endl;

        //cout << start.x << "--" << start.y << "--" << start.z << endl;
        //cout << endd.x << "--" << endd.y << "--" << endd.z << endl;

        int tim = bfs();
        if (tim != -1)printf("Escaped in %d minute(s).\n", tim);
        else printf("Trapped!\n");

    }
    //cout << "2" << endl;
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
const int N=100010;
int a[N];
int ans;
int main(){
    int n;
    cin>>n;
    for(int i=0;i<n;i++)scanf("%d",&a[i]);
    for(int i=0;i+1<n;i++){
        int delta=a[i+1]-a[i];
        if(delta>0)
            ans+=delta;
    }
    cout<<ans;
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int n;
const int N=100010;
int inf=0x3f3f3f3f;
int a[N];
long long b[N];
int main(){
    memset(b,0,sizeof b);
    cin>>n;
    int j=1;
    long long maxx=-inf;
    for(int i=1;i<=n;i++){scanf("%d",&a[i]);
    }
    //cout<<cnt<<endl;;
    for(int i=1;i<=n;){
        while((i<pow(2,j))&&(i<=n)){
            b[j]+=a[i++];
        }
        maxx=max(maxx,b[j]);
        j++;
    }
    //for(int i=1024;i<=10000;i++)cout<<a[i]<<"-";
    int ans=0;
    //cout<<j<<endl;
    for(int i=1;i<=j;i++){
        //cout<<b[i]<<endl;
        if(b[i]==maxx){
            ans=i;
            break;
        }
    }
    cout<<ans;
    return 0;
}

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

const int N=10010;
int a[N];
int n;
int find(int x,int l){
    for(int i=l;i<=n;i++)
        if(x==a[i])return i;
    return -1;
}
int main(){
    cin>>n;
    for(int i=1;i<=n;i++)scanf("%d",&a[i]);
    int b[N];
    memcpy(b,a,sizeof a);
    sort(b+1,b+1+n);
    int cnt=0;
    for(int i=1;i<=n;i++){
        if(a[i]!=i){
            int x=find(i,i);
            //cout<<x<<endl;
            a[x]=a[i];
            cnt++;
        }
    }
    cout<<cnt<<endl;
    return 0;
}