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Codeforces Round #424 (Div. 2, rated, based on VK Cup Finals)

D题fst了,生无可恋。第二场rated的CF,打得精神恍惚

A. Unimodal Array
题意:判断数列是否是单峰的。
像题意那样分为三个阶段随便判一判就好了
#include<iostream>#include<cstdio>#include<cstring>#include<cstdlib>using namespace std;int n,x[105],part=1;bool f=1;int main(){    scanf("%d",&n);    for(int i=1;i<=n;i++)    {        scanf("%d",&x[i]);        if(part==1)        {if(x[i]==x[i-1])part=2;else if(x[i]<x[i-1])part=3;}        else if(part==2)        {if(x[i]<x[i-1])part=3;else if(x[i]>x[i-1]){f=0;break;}}        else if(part==3)        {if(x[i]>x[i-1]){f=0;break;}else if(x[i]==x[i-1]){f=0;break;}}    }    if(f)printf("YES\n");    else printf("NO\n");    return 0;}
B. Keyboard Layouts
题意:给出一个26个字母的对应方式, 将给定串由模式1转为模式2
模拟,判断一下大小写
#include<iostream>#include<cstdio>#include<cstring>#include<cstdlib>using namespace std;char a[26],b[26],s[1001];int map[26];int main(){    scanf("%s%s%s",a,b,s);    for(int i=0;i<26;i++)    map[a[i]-a]=b[i]-a;    for(int i=0;i<strlen(s);i++)    {        if(s[i]>=a&&s[i]<=z)cout<<(char)(map[(int)(s[i]-a)]+a);        else if(s[i]>=A&&s[i]<=Z)cout<<(char)(map[(int)(s[i]-A)]+A);        else cout<<s[i];    }    return 0;} 
C. Jury Marks
D. Office Keys
题意:给出n个人,k把钥匙,和办公室所在位置,每个人都需拿到一把钥匙再去办公室,最小化他们之中的最大路程
没错…这题我fst了,二分边界开小了,并且某处忘记了j++,心痛
二分答案,然后贪心思路:直觉上可以知道人与钥匙一一对应是从左到右的,根据这点判断是否可行
#include<iostream>#include<cstdio>#include<cstring>#include<cstdlib>#include<algorithm>typedef long long LL; int n,k,p,a[1005],b[2005];using namespace std;LL dis(LL x,LL y){return abs(y-x)+abs(p-y);}bool check(LL mid){    int j=1;    for(int i=1;i<=n;i++,j++)    {        while(j<=k&&dis(a[i],b[j])>mid)++j;        if(j>k)return false;    }    return true;}int main(){    scanf("%d%d%d",&n,&k,&p);    for(int i=1;i<=n;i++)scanf("%d",&a[i]);    for(int i=1;i<=k;i++)scanf("%d",&b[i]);    sort(a+1,a+1+n),sort(b+1,b+1+k);    LL l=0,r=2000000000,ans;    while(l<=r)    {        LL mid=(l+r)>>1;        if(check(mid))ans=mid,r=mid-1;        else l=mid+1;    }    printf("%I64d\n",ans);    return 0;}
E. Cards Sorting
F. Bamboo Partition

Codeforces Round #424 (Div. 2, rated, based on VK Cup Finals)